Life Processes ...

The human intestine is long because:

The main waste component present in the blood, that needs to be filtered when the blood passes through the dialysing fluid of a dialysis machine is:

A transport system is needed to transport
(i) Nutrients, oxygen and hormones from the place, they are absorbed or received to the cells.
(ii) Waste products from the place they are formed to the place from where they are eliminated outside.
(iii) Heart beat, chromosome.

A schematic representation of the blood circulation is given. Which of the circulatory parts are incorrectly placed in it?

Blood pressure in the veins is lower than that of arteries. The best hypothesis to explain this is that 

If the rate of translocation of food is slow then the rate of photosynthesis will:

Most of the carbon dioxide in the blood is carried in the form of 

Blood enters the heart because of the 

Which of the following regions of the alimentary canal of human beings does not secrete a digestive enzyme?

Consider the following statements regarding blood pressure.
1. It is the pressure exerted by the blood on the walls of any blood vessel.
2. It decreases in the arteries as the distance from the heart increases.
3. It is lower in the capillaries than in the arteries.
4. It is usually lower in women than in men.