The cellular elements found in highest number in blood are

1. RBCs
2. lymphocyte
3. eosinophils
4. basophils

The difference between the birth rate and the death rate is called

1. natality
2. mortality
3. growth rate of population
4. population density

Transpiration is highest during the summer. Which of the following reasons supports this statement?

P. Increase in temperature allows more water to evaporate.

Q. Warm air can hold more water than cold air.

R. Increase in temperature allows less water to evaporate.

1. Only P
2. Only R
3. Only P and Q
4. Only Q and R

The cones contain the pigment

1. rhodopsin
2. visual purple
3. iodopsin
4. Both 1 and 2