What is common for cuscuta, ticks and leeches?

In each of the following situations what happens to the rate of photosynthesis?

(i) Cloudy days

(ii) No rainfall in the area

(iii) Good manuring in the area

(iv) Stomata get blocked due to dust

(v) What causes movement of food inside the alimentary canal?

Name the energy currency in the living organisms. When and where is it produced?

Explain the role of mouth in digestion of food.

Why do veins have thin walls as compared to arteries?