SOLVED PAPER 2024 (CDS) (II) (General Knowledge)

Total Questions: 120

1. Which one among the following is not a micronutrient for plants?

Correct Answer: (c) Magnesium
Solution:Magnesium is not a micronutrient for plants. Nutrients are required for the growth and development of plants, which can be divided into two categories based on the required quantity.

Macronutrients: Plants require these in large quantities, e.g., Carbon, Hydrogen, Oxygen, Nitrogen, Phosphorus, Potassium, Sulphur, Magnesium, Calcium.

Micronutrients: Plants require these in relatively small quantities, e.g.,Iron, Molybdenum, Boron, Chlorine, Copper, Zinc, Nickel, Manganese.

Magnesium plays an important role in the formation of chlorophyll, enzyme activities and phosphorus metabolism in plants.

Due to magnesium deficiency, symptoms like yellowing of leaves, falling of leaves, slow growth, etc., are seen in plants.

2. Xylem in the plants are responsible for the transport of

Correct Answer: (b) water and dissolved minerals
Solution:Xylem transports water and dissolved minerals absorbed by the roots to different parts of the plant.

Phloem transports food produced in the leaves to different parts of the plant.

Xylem and phloem together form the vascular system in plants which plays an important role in the exchange of substances between different parts of the plant.

Exchange of gases in plants occurs mainly through stomata.

3. Which one among the following hormones inhibits the growth activity in plants?

Correct Answer: (c) Abscisic acid
Solution:Abscisic acid (ABA) is also called the 'stress hormone' of plants, which inhibits growth activity in plants. When plants face drought, cold or other stressful conditions, the production of abscisic acid increases.

Abscisic acid is responsible for leaf fall, seed dormancy, closing of stomata, inhibition of plant growth etc.

It helps the plant to deal with adverse conditions. Abscisic acid antagonizes the effects of other growth promoting plant hormones such as auxins, gibberellins and cytokinins.

4. Which of the following category of biomolecules does Starch belong to?

Correct Answer: (b) Carbohydrate
Solution:Starch is a complex carbohydrate stored by plants as food.
Carbohydrates are the main source of energy for living organisms.
Starch is a polymer of glucose molecules, i.e., it is made up of many monomer units of glucose.
Starch is stored in the roots, stems, seeds and fruits of plants.

5. Which one among the following is not a feature of Xerophytes?

Correct Answer: (b) Large number of stomata
Solution:Xerophyte plants does not have large number of stomata as they are adapted to live in dry and hot environments such as deserts.

Stomata are small pores on the surface of leaves through which plants exchange gases and at the same time water is also lost as vapour due to transpiration.

In xerophyte plants, the number of stomata is reduced and they are located in the pit to reduce transpiration.

In xerophyte plants, stomata usually open at night and carry out gaseous exchange.

Other adaptations in xerophyte plants are- deep spread of roots, thick and fleshy stem, presence of thorns in place of leaves.

Examples of xerophyte plants are cactus, aloe, etc.

6. Halophytes are the plants that grow on which one, among the following categories of soil?

Correct Answer: (b) Saline soil
Solution:Halophyte plants grow on saline soil.

The amount of soluble salts in saline soil is very high. These salts are mainly chlorides and sulphates of sodium, magnesium and calcium.

Halophyte plants are found in mangrove forests. They grow on the submerged coastal areas and protect this area from erosion.

7. Which one among the following is not a part of vascular bundle in plants ?

Correct Answer: (d) Endodermis
Solution:Endodermis is an important cellular layer found in the roots of plants. It is not a part of the vascular bundle, but controls the flow of water and mineral salts.

The vascular bundle transports water, mineral salts and food to different parts of the plant.

The vascular bundle is made up of two main complex tissues, xylem and phloem.

Xylem transports water and mineral salts from the roots to different parts of the plant.

Phloem carries food produced in the leaves to other parts of the plant.

Vascular cambium is a meristematic tissue located between xylem and phloem, which plays an important role in the formation of secondary xylem and phloem of the plant.

8. In which one among the following mediums would the speed of sound be maximum?

Correct Answer: (b) Sea water
Solution:The speed of sound will be maximum for the denser medium. Among the given options, sea water has highest density. So, the speed of sound would be maximum in the seawater.

The densities of the given medium in decreasing order are Sea water > Drinking water > Distilled water > Methanol.

9. Which organelle in animal cells can digest foreign materials?

Correct Answer: (b) Lysosome
Solution:Lysosomes digest foreign materials.

Their main function is to digest the waste materials present inside the cell.

Other functions of lysosomes are related to intracellular digestion of reserve food, digestion of foreign substances, disintegration of damaged organelles and cell death.

Lysosomes are formed by Golgi bodies.

Lysosomes are membrane bound, small, sac-like structures found inside the cell.

Hydrolytic enzymes are present in lysosomes.

The pH of lysosomes is acidic, because the enzymes of lysosomes are active only in acidic medium.

10. Photosynthesis that converts light energy into chemical energy by the plants, involves the use of green pigments of leaves called chlorophyll. The only structure in a leaf that hosts chlorophyll is

Correct Answer: (c) chloroplast
Solution:Chloroplast is the only structure in a leaf that hosts chlorophyll.

Photosynthesis that converts light energy into chemical energy by the plants, involves the use of green pigments of leaves called chlorophyll. The only structure in a leaf that hosts chlorophyll is chloroplast.

The green colour of the leaves of plants is due to the presence of chlorophyll pigment.

Chlorophyll pigment absorbs sunlight in the process of photosynthesis.

Chlorophyll pigment is found in chloroplasts in plant cells. Thus, the process of photosynthesis takes place in chloroplasts.