Class 11 Biology NEB Past Questions

1. 2076 Set C Q.No. 22 Types of amino acid. There are total 200 amino' acids found in nature. They are classified into non protein aminoacids ard protein amino acids. Protein

2. 2076 Set B Q.No. 2b) Types of lysosomes. Lysosomes are the main digestive compartment of the cell. As such, they contain a variety of 'enzymes capable of degrading different types of biological material including nucleic acids, lipids and proteins among others. They can be found in animal cells and some plant cells (occurring as vacuoles) ard are capable of breaking down various types of macromolecules brought in to the cell to be degraded. Most of these macromolecules are either damaged or have completed their life cycle and are no longer useful. Lysosomes are following types. a. Primary Lysosome: They are newly pinched off vesicles from the Golgi apparatus which generally fuse with some endosomes to become fully functional. The primary lysosomes are small in size. They contain hydrolytic enzymes in the form of granules. b. Secondary Lysosome: They are also called heterophagosomes or digestive vacuoles. A secondary lysosome is formed by the fusion of food containing phagosome with lysosome (having hydrolytic or digestive enzymes). Digestion occurs. The digested food passes out into the cytoplasm. Finally, the secondary lysosome is left with undigested food. c. Autolysosome/Autophagic Vacuole:

3. 2076 Set C Q.No. 2E Types and

4. 1. 2076 Set B Q.No. 2c Kinds of chromosome. Chromosomes are thread-like structures located inside the nucleus of animal and plant cells. Each chromosome is made of protein and a single molecule of deoxyribonucleic acid (DNA). Passed from parents to offspring, DNA contains the specific instructions that make each type of living creature unique. The term chromosome comes from the Greek words for color (chroma) and body (soma): Types of chromosomes Chromosomes are divided into two parts central constriction point called a centromere and terminal part called chromatids. The centromere can be located in different positions and this forms the basis for the four different classes of chromosome a. Metacentric chromosomes: Metacentric chromosomes have the ceritromere in the center, such that both sections are of equal length. Human chromosome 1 and 3 are metacentric. b. Submetacentric chromosomes: Submetacentric chromosomes have the centromere slightly offset from the center leading to a slight asymmetry in the length of the two sections. Human chromosomes 4 through 12 are submetacentric. C. Acrocentric chromosomes: Acrocentric chromosomes have a centromere which is severely offset from the center leading to one very long and one very chromosomes 13, 15, 21, and 22 are acrocentric. d. Telocentric chromosomes: Telocentric chromosomes have the centromere at the very end of the chromosome. Humans do not possess telocentric chromosomes but

5. 2076 Set B Q.No. 2a Functions of carbohydrate. Functions of

6. 2076 Set C Q.No. 2c Structure of chromosome. Structure and regions recognized in chromosomes: Secondary constrictior Structurally, each chromosome is differentiated into seven parts: a. Pellicle:

7. 2. 2076 Set C Q. No. 2f Discuss significance of bird migration. Bird migration is the regular seasonal movement, often

8. 1. 2076 Set B Q. No. 2 Terrestrial adaptations of animal. A biological adaptation is any structural (morphological or anatomical), physiological, or behavioral characteristics of an organism or group of organisms (such as species) that make it better suited in its environment and consequently improves its chances of survival and reproductive success. Terrestrial adaptations are exhibited by the animals living in land habitats. As there are varied types of land habitats, the adaptations shown by animals also are of diverse kinds. [1 Mark] 6. 1. 8. 9. 10. b d [5 Marks] Unit - 9: BIOTA AND ENVIRONMENT 257 i. Cursorial Adaptation: Cursorial animals are those animals which live in open places and are adapted to run on hard ground e.g. lion, deer, horse etc. Adaptational characters of them are as follows: The body is streamlined which helps them for swift movement. The limbs are long and strong Locomotion is digitigrade. ii. Fossorial Adaptation: Fossorial animals are those animals which are adapted for burrowing mode of life e.g. rabbit, rat, etc. The adaptational characters of them are as follows: The head is small and tapers anteriorly to form snout for digging. .. The forelimbs are short with powerful claws. The eyes and the ears are small. iii. Arboreal Adaptation (Scansorial Adaptation):

9. 1. 2076 Set B Q. No. 2d List out the sources of pollutants. A pollutant is a chemical or biological

10. 1. 2076 Set B Q. No. 2g Causes of depletion of wildlife. . The causes of depletion of wildlife can

11. 1. 2076 Set B Q.No. 4 Define ecosystem and describe the structural and functional aspects of pond ecosystem with suitable examples. Ecosystem is the basic functional unit with which ecology deals since it includes both the organisms and non living environment, each influencing the properties of the other and both necessary for the maintenance of life on earth. A pond ecosystem refers to fresh water ecosystem where there are communities of organism dependent on each other with the prevailing water environment for their nutrients and survival. Usually ponds are shallow water bodies with a depth of 12-15 feet in which the sun rays can penetrate to the bottom permitting the growth of plants there. On the basis of water depth, penetration of light and types of vegetation animal's ponds can be divided into three zones i.e Littoral, Limnetic and Profundal Zone. littoral 6 meters zone 10 meters sublittoral zone profundal zone Components of Pond Ecosystem Pond ecosystem consists of structural components and functional components Structural Components Abiotic components and biotic components are structural and functional components of an ecosystem Abiotic Factors or Components The abiotic substances of Pond ecosystem are formed as a result of the mixture of some organic and inorganic materials. The basic components are water, oxygen, carbon dioxide, salts of calcium and nitrogen etc. Only a small amount of these elements are present in soluble state in pond water, but a large amount is held in reserve solid form in the bottom sediments as well as within the organisms. Various organisms get their nourishment from these abiotic Unit: 4: ECOLOGY 131 [8 Marks] lake surface - compensation level no photosynthetic, organism substances. The rate of release of reserve nutrients, the solar input and the cycle of temperature, day length and other climatic conditions regulate the

12. 1. 2076 Set C Q. No. 2e Give general characters of Neanderthal man. Neanderthal man or Homo nearderthalensis was the ancestor of modern man. Their fossils were found at the Feldhover cave of Neander valley of Germany in 1856. They lived on earth from 400,000 to 40,000 years ago in Europe and Southwestern to Central Asia during the Ice Age. 'Many of their fossils have been recovered from the caves, so,

13. 1. 2076 Set B Q. No. 2075 Set A Q.No. 2g) 2070 Supp Q. No. 2E 2070 Set D Q.No.

14. 1. 2076 Set B Q. No. 4 2071 Set C Q.No. 4 Explain the most accepted theory of origin of

15. 2. 2076 Set B Q. No. 2e 2071 Set D Q.No. 2f Differentiate between chondrichthyes and oesteíchthyes. The

16. 1. 2076 Set C Q. No. 2g Discuss mechanism of breathing in frog Breathing is a process by which the

17. 1. 2076 Set B Q. No. 3 What is portal system? Describe the Venous System of frog. Portal system can be defined as a part of the systemic circulation, in which blood draining from the capillary bed of one structure flows through larger vessels to supply the capillary bed of another structure, before returning to the heart. Simply, a system of blood vessels that begins and ends in capillaries is called portal system. The veins and their tributaries constitute the venous system. The arteries break up into smaller and smaller branches, and these branches merge into a network of thin-walled, hair- like vessels, called capillaries. The capillaries merge into small veins, which join to form larger veins. The Venous system of Frog is divided into three separate groups: i. The pulmonary venous system ii. The systemic venous system, and ili. The portal venous system. i. › Pulmonary Venous system: Two pulmonary veins carry oxygen-rich blood from right and left lungs. The right and left pulmonary veins unite to form a common pulmonary vein, which opens into the left auricle on the dorsal side. ii. - Systemic Venous system: This system is represented by the three large caval veins draining into the corners of the triangular sinus venous. They carry oxygen-poor blood from all parts . of the body except lungs. Two of the caval veins are situated anteriorly; these are the right and left precaval. A single postcaval is found posteriorly, opening into the apex of the sinus venosus. Each precaval vein is formed by the union of three tributaries: a. External jugular: The external jugular vein is formed by the union of two tributaries -a lingual vein bringing blood from the tongue, and a mandibular vein from the jaws and snout: b. Innominate: The innominate vein is also formed by the union of two tributaries-an internal jugular vein from the interior of the skull, and a subscapular from 'the back of the shoulder. c. Subclavian: The subclavian vein is formed by the unior of two veins - brachial vein from the forelimb and musculo-cutaneous vein from the skin and muscles. In frog, the skin is an accessory respiratory organ. Hence the blood carried by the musculo-cuta- neous vein is comparatively rich in oxygen. The postcaval vein has its roots in the kidneys.

18. 3. 2076 Set C Q. No. 2d Write down outline

19. 1. 2076 Set B Q. No. 2b Liver schizogony in malarial parasite. The Plasmodim life cycle involves two host. During

20. 2. 2076 Set B Q. No. 2c Structure and

21. 1.- 2076 Set B Q. No. 3. OR Describe the reproductive system of earthworm Earthworms reproduce sexually.

22. 2. 2076 Set C Q. No. 3. OR Discuss physlology of digestion in frog. Digestion is a process by which the non-diffusible food material is converted into diffusible form by the action of various digestive enzymes. The three main food stuffs carbohydrate or starch, protein and fat should be converted into glucose, amino acids, fatty acids and glycerol, respectively. The process of food digestion can be described as follows: 1. Food and its Ingestion: The adult frog is carnivorous and feeds on insects, earthworms, molluscs, small sized fishes, etc. The tadpoles are however, herbivorous in nature. The digestive process of frog starts with ingestion, which involves catching their prey (flies, spiders, slugs, other, insects, and smaller animals that can fit into their mouth) with their sticky, cleft or bilobed tongue, and swallowing it. They use their maxillary teeth for holding on the prey. Their sticky tongue prevents the prey from fleeing. The vomerine teeth paralyze the prey. Frogs mostly swallow their prey whole. This process is referred to as deglutition. While doing so, they blink or close their eyes, pushing them down through openings in the skull. This helps to propel the food towards the oesophaus. The peristalsis aid in the downward movement of the food into the stomach. The peristalsis is due to the alternate contraction and distension of the longitudinal and circular muscle present in the alimentary canal. The mucous membranes of the mouth and oesophaus produce mucus which helps in the slippery movements of food. 2 Digestion in the stomach (Gastric Digestion): Digestion starts in the stomach. In the stomach the food undergoes mechanical digestion and then chemical digestion. i. Mechanical digestion: When the food reaches the stomach through the oesophagus, the wall of the stomach releases a hormone called gastrin which stimulate the gastric glands to release gastric juice and hydrochloric acid. The rhythmic contraction and relaxation of the stomach wall churns the food into smaller pieces. The oxyntic cells of the mucosa epithelium release hydrocholic acid, which acidifies the churned food. The mucous glands in the lining of stomach secrete mucus and lubricate the food. Now the churned food undergoes chemical digestion. ii: Chemical digestion: It involves the action of enzymes upon the churned food. The zymogen cells or peptic cells present in the stomach lining release a pro-enzyme called pepsinogen which is inactive. Role of Hydrochloric acid It converts inactive pepsinogen into active pepsin. It provides acidic medium upon which pepsin can act on protein. It kills the microorganisms present in the food. Protein digestion starts in the stomach. The hydrochloric acid converts the inactive pepsinogen into active pepsin. The pepsin cleaves the proteins into proteoses and peptones. Pepsinogen (Inactive) - HCI → Pepsin (Active) Proteins _ Pepsin, Proteoses + Peptones The carbohydrates and fats remain unaffected by the proteolytic enzymes. Due to massive peristalsis of the stomach wall, the food is converted into a semi-solid mass known as chyme. The food remains in the stomach for 2 to 3 hours. The chyme passes into the duodenum through pyloric sphincter at regular intervals. 3. Digestion in the Duodenum (Intestinal Digestion): In the duodenum the chyme is affected by the bile, pancreatic and intestinal juice. i. Role of bile: As soon as the food reaches the duodenum, its wall releases a hormone called cholecystokinin, which travels to the gall bladder through the blood circulation. CamScannel This hormone brings about the contraction of gall bladder to pour out bile into the duodenum through hepato-pancreatic duct. Bile is an alkaline fluid which neutralize the 'acidic nature of the chyme and converts the PH into slightly alkaline to make an effective action of Pancreatic juice for the digestion. Acidic food Bile Alkaline food. The bile salts lower down the surface tension of fat material, which is broken down into fine droplets or globules. This process is called emulsification. 5 r'Bile Fats — Emulsification → smaller fat globule ii. Role of Pancreatic juice: After the food is made slightly alkaline, the duodenal wall secretes a hormone called secretin, which reaches the pancreas through blood circulation and stimulates the pancreas to release pancreatic juice. The pancreatic juice contains three powerful enzymes which hydrolyze all three classes of food. These enzymes are trypsinogen, pancreatic amylase or Amylopsin, and Pancrèatic lipase or Steapsin. a. Role of Pancreatic Amylase: The Pancreatic Amylase hydrolyzes the carbohydrate or starch into glucose or maltose. Carbohydrate/Starch Amylopsin:, Glucose/ Maltose b. Role of Pancreatic Lipase: The Pancreatic Lipase or Steapsin converts the emulsified fats into fatty acids and glycerol. Emulsified Fats Steapsin, Fatty acids + Glycerol. c. Role of Trypsin: The intestinal mucosa releases an enzyme called enterokinase, which converts the inactive trýpsinogen into active trypsin. The trypsin is a proteolytic enzyme and converts the proteins or proteoses and peptones into amino acids or smaller polypeptides, tripeptides or dipeptides. Trypsinogen (Inactive) _ Enterokinase, Trypsin (Active) Proteins / Proteoses + Peptones Trypsin, Peptides + amino acids. iii. Role of Intestinal Juice (Succus Entericus) The duodenum secretes another hormone called enterocrinin, which activates the secretion of intestinal juice or succus entericus. The intestinal juice contains peptidase, maltase, sucrase, and lipase. a. Role of Peptidases: The tripeptides and dipeptides are converted into amino acids by the action of tripeptidase and dipeptidase. Tripeptides Tripeptidase → Amino acids Dipeptides. Dipeptidase → Amino acids Polypeptides Polypeptidase, Amino acids b. Role of Maltase and Sucrase: The Maltase converts the maltose into glucose. The sucrase converts the sucrose into glucose and fructose. Maltose Maltase* Glucose® :) Sucrose Sucrase, Glucose + Fructose. c. Role of Intestinal Lipase: The intestinal lipase hydrolyzes the remaining fats into fatty acids and glycerol, Remaining fats Intestinal Lipase, Fatty acids + Glycerol. 4. Digestion in the Ileum: Majority of the digestion occurs in the dudoenum. However, the remaining carbohydrates, proteins and fats are digested by the intestinal juice in the ileum. In this way complete digestion of three main classes of food takes place in the ileum. CamScannel 5. Absorption:

23. 1. 2076 Set B Q.No. 2e Economic Importance of gymnosperm. Gymnosperm is the small group of plants, which constitutes a

24. 1. 2076 Set B Q.No. 2f Types of stem. > The stem is the ascending part of the plant formed by the elongation of the plumule of the embryo. It bears leaves, branches and flowers. a. Underground stem: Underground stems are modified plant structures that derive from tissue but exist under the soil surface. They function as storage tissues for food and nutrients, propagation of new clones, and perennation (survival from one growing season to the next). Different forms of underground stems include: Bulb Tulips, Lilies, onion etc.Corm: Colocasia, Corcus Rhizome: eg Ginger, Banana etc Tuber: eg potato b. Sub aerial stem: Sub aerial stem also takes parts in vegetative reproduction. Its modifications are as follows i. Sucker: A shoot that arises from an underground root or stem. e.g mint, ii. Runner: A stem that grows horizontally along the soil surface and gives rise to new plants either from axillary or terminal buds, e.g Strawberry, Stolon: A long aerial stem that gives rise to a new plan, when its apical bud touches the soil. eg Jasmine iv. Offset: A horizontal short, more or less thickened stem in hydrophytes plants. It helps in vegetative propagation. e.g Eichhornia, C. Aerial stem: In several plants aerial parts of stem like phylloclades, cladodes and bulbils etc help in vegetative reproduction. i. Phylloclades: A flattened, photosynthetic branch or stem that resembles or performs the

25. 2. 2076 Set C Q.No. 2e Female cone of Pinus. Female cone: Observe the external features and longitudinal section of

26. 1. 2076 Set B Q.No. 3 Describe the structure and sexual reproduction in Marchantia with suitable diagrams. Systematic Position of Marchantia . Division *: Bryophyta Class : Hepaticopsida Order : Marchantiales Family : Marchantiaceae Genus : Marchantia Distribution and Habitat of Marchantia Marchantia, the most important genus of family Marchantiacee is represented by about 65 species. The name Marchantia was given in honour of Nicolas Merchant, director of botanical garden of Gaston d' Orleans in Blois, France. All species are terrestrial and cosmopolitan in distribution. The species prefer to grow in moist and shady places like wet open woodlands, banks of streams, wood rocks or on shaded stub rocks. These grow best after the forest fire in the burnt soil. It is perhaps because of nitrification of soil due to fire (Richard, 1958). Some of the common Nepali species are M. palmata, M. polymorpha, M. polymorpha. M. polymorpha var aquatic grows submerged in swampy meadows. The thalli with gemma cups are found throughout the year whereas the thalli with sex organs occur abundantly during February to March in Himalayas and October to November in hills. Unit - 2: FLORAL DIVERSITY 75 Sporophyte It is diploid phase of life cycle. It produces spores called meiospores. Meiosis occurs during formation of meiospores. It is asexual generation. Meiospores form gametophytes. It is formed by growth of a zygote. [8 Marks] CamScannel Morphology The plant body is gametophytic, thalloid, fat, prostrate, plagiotropic, 2-10 cm. long and dichotomously branched. Dorsal surface: Dorsal surface is dark green. It has a conspicuous midrib and a nuthber of polygonal areas called areolae. The midrib is marked on. the dorsal surface by a shallow groove and on the ventral surface by a low ridge. Each polygonal area re-presents the underlying air chamber. The boundaries of these areas represent the walls that separate each air chamber from the next. Each air chamber has a central pore. The midrib ends in a depression at the apical region forming an apical notch in which growing point is situated. Dorsal surface also bears the vegetative and sexual reproductive structures. The vegetative reproductive structures are gemma cup and develop along the midrib. These are crescent shaped with spiny or fimbriate margins and are about one eighth of a inch in diameter. Sexual reproductive structures are borne on special Stalked structures called gametophores or gamctangiophores. The gametophores bearing archegonia are called archegoniophores and that bearing antheridia are called antheridiophores. Ventral surface: The ventral surface of the thallus bears scales and rhizoids along the midrib. Scales are violet coloured, multicellular, one cell thick and arranged in 2-4 rows. Scales 'are of two types: i. Simple or ligulate ii. Appendiculate: Appendiculate scales form the inner row of the scales close with midrib. Ligulate scales form the outer or marginal row and are smaller than the appendiculate scales. Rhizoids are unicellular, branched and develop as prolongation of the lower epidermal cells. They are of two types: a: Smooth-walled rhizoids b. Tuberculate rhizoids: In smooth-walled rhizoids both the inner and outer wall layers are fully stretched while in tuber-culate rhizoids appear like circular dots in surface view. The inner wall layer modifies into peg like in growth which projects into the cell lumen. The main

27. 1. 2076 Set B Q.No. 3 OR 2073 Set C Q.No. 3 OR 2071 Supp Q.No. 3 OR Describe the family cruciferae in semi- technical terms with identifying characters, floral diagram and floral formula with two examples of economic value. Family-Cruciferae (Brassicaceae) The cruciferae is also known as mustard family. This family includes 375 genera and 3250 species 38 genera and 98 species are reported in Nepal.This family is cosmopolitan is distribution. The plants are found abundantly in northern hemisphere and distributed worldwide. This family includes vegetables flowers and wild varieties. Habit/Habitat: Annual or biannual. or sometimes perennial, herbs, rarely shrubs, wild or cultivated, terrestrial, mesophytic. Vegetative Structure Root: Tap root and branched or modified (fusiform e.g. Raphnus sativus, Napioform (e.g B.rapa), sometimes adventitious e.g. Roripa. Stem: Erect, herbaceous, branched, cylindrical, solid, hairy or glabrous, green, sometimes stem is condensed or thickened (B. oleraces, R. sativs) Leaf: Exstipulate, petiolate or sessile, alternate, rarely, opposite, simple, cauline and ramal or radical, lyrate, lobed or entire, acute, glabrous, unicostate, reticulate venation. Floral Characteristics Inflorescence: racemose, receme or corymb Flower: Ebracteate, ebractiolate, pedicellate, zygomorphic, hypogynous, tetramerous, small, white or yellow. Unit -Z: FLORAL DIVERSITY 103 Disc floretes Flower is illigulated, hairy no extra- appendage.

28. 2. 2076 Set C Q.No. 2f Types of leaf. & Leaf is a flattened exogenous lateral outgrowth, developed from node of the stem and helps in photosynthesis, transpiration and exchange of gasaes. Leafs are of two types a.. Simple Leaf: In simple leaf, leaf lamina may be incised or may not be incised. If leaf lamina is incised, incised parts do not touch to the mid vein. Simple can not form leaflets or pinna. eg Leaf of Mango b. Compound Leaf: In compound leaf, leaf lamina is incised and forms leaflets or pinna.

29. 1. 2076 Set B Q.No. 2d Structure of Nostoc. Morphology: Nostoc is a colonial cyanophyte. Colonies are ball-shaped. Each colony

30. 2. 2076 Set C Q.No. 2d Economic Importance of bacterla. Economic importance of bacteria Bacteria have been used in the field of agriculture, industry and medicine a. Role in Agriculture i. Decay and decomposition: Soil bacteria play an important role in bringing about decomposition of organic matter. They serve a double purpose. In the first instance they act as scavengers removing harmful waste from the earth. Secondly, they return it to the soil as plant food. The dead bodies and wastes of organisms (both plants and animals) are decomposed by the activities of the saprophytic bacteria. ii. Soil fertility: Some bacteria play an important role in maintaining and others in increasing soil fertility. The fertility of soil is proportional to its nitrogen content. Nitrogen is an essential ingredient of all living protoplasm. All growing plants, therefore, require it in their metabolism. Ammonifying Bacteria Nitrifying Bacteria b. Role of Bacteria in Industries: Man has utilised the activities of bacteria for various industrial processes. The butter and cheese industries entirely depend upon the activities of the lactic acid bacteria. Many saprophytic bacteria in their metabolic activities excrete waste products of great commercial importance. i. Lactic acid:

31. 2075 Set A Q.No. 2b Describe the various endoplasmic reticulum. Endopalsmic reticulum is a single membrane bound cell oragnelles present in all eukarotic cells (except mammalian RBC, eggs, and embryonic cells). It is a complicated network formed by cisternae, vesicles and tubules. Based on their functions endoplasmic reticulum is divided into two types 1. Smooth endoplasmic reticulim or Agrannular (SER) It has smooth membrane not associated with ribosome and abundantly present near to cell membrane. SER present in cells which are involved in lipid synthesis. It is mainly consisting of tubules and vesicles.

32. 4. 2075 GIE Q.No. 20

33. 3. 2075 Set A Q.No. 2g Elaborate the significance of melosis. The main significance of meiosis are: i. Formation of

34. 6. 2075 Set A Q.No. 2g Describe the structure and

35. 2075 Sot B Q.No. 2b Structure and

36. 2075 Set B Q.No. 2a Proteins and its function. Proteins are polymers of twenty kinds of amino acids. In proteins amino acids are joined by peptide bond. Peptide bond is formed by condensation of two neighboring amino acids producing molecules of water. Proteins are the most complex chemical compounds formed of C, H, O, N, S, P: The characteristics element of proteins is nitrogen. All the reactions in the body are controlled by proteins, which are known as enzymes. Proteins are the chief body builders of the body. Proteins are used to synthesize enzymes (eg, pepsin, trypsin), hormones (e.g., insulin, adrenaline), carrier proteins (e.g., Haemoglobin), contractile proteins (e.g., myosin, actin), structural proteins (e.g., collagen) and protective proteins (antibodies). They also form skin pigments like melanin and nucleic acids of the genetic material, DNA and RNA - purines and pyrimidines.Normal protein requirement of an adult is 1g/kg of the body weight. However, growing children, pregnant and nursing mothers need more proteins.. The main

37. 2. 2075 GIE Q.No. 2g Process of melosis II.

38. 2075 GIE Q.No. 22 2072 Set C Q.No. 2z Blological role of water.

39. 2. 2075 GIE Q. No. 2f How would you prevent air pollution? The control measures of air pollution can be

40. 3. 2075 Set B Q.No. 2f Briefly state on leadership and dominance of animal with sultable examples. A. Leadership in Animals: Leadership is the ability of the individual in a group to lead and to provide proper guidance to their members by going in front and drawing others along the same course. The primary