Nutrition

Step 1: Understanding DNA structure.
DNA consists of two antiparallel polynucleotide strands forming a double helix.

Step 2: Base pairing mechanism.
Complementary nitrogenous bases pair with each other through hydrogen bonds: adenine with thymine via two hydrogen bonds and guanine with cytosine via three hydrogen bonds.

Step 3: Eliminating other options.
Phospho-di-ester bonds join nucleotides within a strand, peptide bonds join amino acids, and glycosidic bonds link sugars to bases.

Step 4: Conclusion.
Thus, complementary nucleotides in DNA are held together by hydrogen bonds.

Step 1: Understanding Hisardale.
Hisardale is an improved breed developed for better wool quality and yield.

Step 2: Method of development.
It was developed in Punjab by cross-breeding Bikaneri ewes with Merino rams.

Step 3: Identifying the animal.
Since both parent breeds are sheep, Hisardale is a sheep breed.

Step 4: Conclusion.
Therefore, Hisardale is a breed of sheep.

Step 1: Understanding water-soluble vitamins.
Water-soluble vitamins are those that dissolve in water and are easily absorbed by the body. These include the B vitamins and vitamin C. They are not stored in large amounts in the body and need to be consumed regularly.
Step 2: Analyzing the options.
(A) Vitamin A and B: Vitamin A is fat-soluble, so this combination is incorrect.
(B) Vitamin B and C: Correct — Both vitamin B (a group of vitamins) and vitamin C are water-soluble.
(C) Vitamin E and K: These are fat-soluble vitamins, so this option is incorrect.
(D) Vitamin C and D: Vitamin D is fat-soluble, making this option incorrect.
Step 3: Conclusion.
The correct answer is (B) Vitamin B and C, as these are the water-soluble vitamins.

Step 1: Understanding biogas composition.
Biogas is produced by anaerobic decomposition of organic matter by methanogenic bacteria.

Step 2: Major components of biogas.
Biogas mainly consists of methane, carbon dioxide, and small amounts of hydrogen sulphide and other gases.

Step 3: Methane percentage.
Methane constitutes about 50–80 percent of biogas, making it a good fuel.

Step 4: Conclusion.
Thus, the percentage of methane in biogas is 50–80.

Step 1: Understanding Kwashiorkor.
Kwashiorkor is a severe form of malnutrition commonly seen in children who receive sufficient calories but lack adequate protein in their diet.
Step 2: Role of proteins.
Proteins are essential for growth, tissue repair, enzyme synthesis, and maintenance of osmotic balance in the body. Deficiency leads to edema, muscle wasting, and growth retardation.
Step 3: Analysis of options.
(A) Proteins: Correct, deficiency causes Kwashiorkor.
(B) Fats: Deficiency leads to energy imbalance but not Kwashiorkor.
(C) Vitamins and minerals: Cause deficiency diseases like scurvy or anemia.
(D) Carbohydrates: Deficiency mainly leads to energy deficiency.
Step 4: Conclusion.
Kwashiorkor is caused mainly due to prolonged deficiency of proteins in the diet.

Step 1: Observing the chemical formula.
The given substrate has a very high proportion of carbon and hydrogen compared to oxygen, as seen in the formula C\textsubscript{51}H\textsubscript{98}O\textsubscript{6}. Such a composition is characteristic of lipids.
Step 2: Comparing respiratory substrates.
Carbohydrates have a C:H:O ratio of approximately 1:2:1, while fats have much less oxygen and more hydrogen. Proteins also contain nitrogen, which is absent here.
Step 3: Energy yield and oxygen requirement.
Fats require more oxygen for oxidation and produce more energy, CO\textsubscript{2}, and H\textsubscript{2}O compared to carbohydrates. The equation shows a large oxygen requirement, supporting fat oxidation.
Step 4: Conclusion.
The respiratory substrate represented in the equation is fat.

Step 1: Understanding mutation breeding.
Mutation breeding is a technique in which mutations are artificially induced using chemicals or radiation to develop desirable traits such as disease resistance in crop plants.
Step 2: Application in moong bean.
Moong bean (Vigna radiata) was subjected to mutation breeding to develop resistance against powdery mildew, a fungal disease that severely affects crop yield.
Step 3: Analysis of options.
(A) Powdery mildew: Correct, as mutation breeding successfully produced resistant varieties.
(B) Black rot: Commonly affects fruits like grapes and cabbage, not moong bean.
(C) Leaf curl: Mostly associated with viral infections in crops like cotton and tomato.
(D) Curl blight: Not related to mutation breeding in moong bean.
Step 4: Conclusion.
Mutation breeding in moong bean was carried out to develop resistance against powdery mildew.

Step 1: Understanding callus in tissue culture.
Callus is an unorganized mass of actively dividing plant cells produced under sterile culture conditions.
Step 2: Role of growth hormones.
Growth hormones like auxins and cytokinins regulate cell division and metabolism in callus tissue.
Step 3: Effect on callus.
Under specific hormonal conditions, callus is induced to synthesize valuable secondary metabolites such as alkaloids and phenolics.
Step 4: Conclusion.
Growth hormones are provided to callus mainly to induce the formation of secondary metabolites.

Step 1: Understanding Kwashiorkor.
Kwashiorkor is a form of malnutrition caused by protein deficiency, typically occurring in children who are weaned off breast milk but are not given sufficient protein-rich food. Symptoms include stunted growth, anemia, protruding belly, and oedema (swelling).
Step 2: Analyzing the options.
(A) Jaundice: Incorrect — Jaundice is a condition characterized by yellowing of the skin due to liver dysfunction, not related to protein deficiency.
(B) Kwashiorkor: Correct — Kwashiorkor is the condition described by the symptoms mentioned, including stunted growth and oedema.
(C) Marasmus: Incorrect — Marasmus is a type of malnutrition caused by both protein and calorie deficiency, but it typically lacks oedema and protruding belly.
(D) Constipation: Incorrect — Constipation is a digestive condition and does not relate to malnutrition or the described symptoms.
Step 3: Conclusion.
The correct answer is (B) Kwashiorkor.

Step 1: Moment of inertia of a single sphere.
The moment of inertia of a single sphere about an axis passing through its center is given by: where is the mass and is the radius of the sphere. Step 2: Moment of inertia of spheres at the corners.
Each sphere is placed at a corner of the square, and the axis of rotation is along one side of the square. For each sphere, we use the parallel axis theorem to calculate the moment of inertia about the axis passing through the side of the square: where is the distance from the center of the sphere to the axis. In this case, . Step 3: Calculate the total moment of inertia.
There are four spheres, and we calculate the total moment of inertia by summing the contributions from each sphere: Simplifying: Step 4: Conclusion.
Thus, the moment of inertia of the system about any side of the square is , which corresponds to option (C).

Step 1: Understanding nitrification.
Nitrification is a biological oxidation process in which ammonia is converted into nitrite and then nitrate by nitrifying bacteria.
Step 2: Analyzing bacterial roles.
Nitrosomonas and Nitrosococcus convert ammonia into nitrite.
Nitrobacter converts nitrite into nitrate.
Step 3: Conclusion.
Since all these bacteria participate in nitrification, the correct answer is (D) Nitrification.