Liver is the largest organ as well as the largest gland of the body.

State whether the following statement is true or false: 'Reptiles have a three-chambered heart,mammals have a four-chambered heart,and fishes have a two-chambered heart.'

Explain how the human body responds when adrenaline is secreted into the blood.

How does the transportation of water occur at night in the absence of transpiration?

In each of the following situations,what happens to the rate of photosynthesis?
$(a)$ Cloudy days
$(b)$ No rainfall in the area
$(c)$ Good manuring in the area
$(d)$ Stomata get blocked due to dust

Which is the first enzyme to mix with food in the digestive tract?