Transpiration helps plants to take up water and mineral salts. In rats, black fur is dominant over white fur. Reptiles are poikilothermic and have scaly skin but are not all terrestrial. Which stateme

Here are the solutions for the questions from the image:

21. Transpiration helps plants to take up:

1. Water
2. Mineral salts
3. Carbon dioxide

• Statement 1 (Water): Transpiration creates a pull that draws water up from the roots. This is correct.
• Statement 2 (Mineral salts): Mineral salts are dissolved in the water and transported upwards with the water due to transpiration. This is correct.
• Statement 3 (Carbon dioxide): Carbon dioxide is taken up through stomata for photosynthesis, not directly by the transpiration stream. This is incorrect.

Therefore, only statements 1 and 2 are correct.
The correct option is B. If 1 and 2 only are correct.

22. In rats black fur colour is dominant over white fur colour. A cross between a homozygous black male and a homozygous white female produces offspring which are all:
Let B represent the dominant black fur allele and b represent the recessive white fur allele.
A homozygous black male has genotype BB.
A homozygous white female has genotype bb.
When crossed (BB $\times$ bb), all offspring will have the genotype Bb. Since black fur (B) is dominant, all offspring will express the black fur phenotype.

The offspring are all: Black

23. Reptiles:

1. Are poikilothermic
2. Have moist scaly skin
3. Are all terrestrial

• Statement 1 (Are poikilothermic): Reptiles are cold-blooded, meaning their body temperature varies with the environment. This is correct.
• Statement 2 (Have moist scaly skin): Reptiles have dry, scaly skin, not moist skin. This is incorrect.
• Statement 3 (Are all terrestrial): While many reptiles are terrestrial, some are aquatic (e.g., sea turtles, crocodiles). This is incorrect.

Therefore, only statement 1 is correct.
The correct option is D. If 1 only is correct.

24. When there is overheating in the body:

1. More blood flows to the skin surface
2. Less blood flows to the skin surface
3. There is an increase in metabolic rate

• Statement 1 (More blood flows to the skin surface): During overheating, blood vessels near the skin dilate (vasodilation) to increase blood flow to the surface, allowing heat to dissipate. This is correct.
• Statement 2 (Less blood flows to the skin surface): This occurs when the body is cold to conserve heat. This is incorrect.