Biology Mcqs

Brown fat present in certain mammals is specialized in___________?

A. Providing insulation in cold environment.
B. Providing insulation in hot environment
C. Rapid heat production.
D. Controlling heat production.

It has been estimated that in a normal person plasma constitutes about ________ by volume of blood.

A. 35%
B. 45%
C. 55%
D. 75%

Which of the following is true about hearts of earthworm?

A. There are 5-7 pairs of heart.
B. They are present between 1-7th segments.
C. They are present lateral to the oesophagus.
D. They pump blood from ventral to dorsal vessel.

Stomata open due to _________ of K+ into the guard cells from the surrounding epidermis

A. Diffusion
B. Active transport
C. Osmosis
D. All of these

Single circuit heart is found in_________?

A. Fishes
B. Amphibians
C. Reptiles
D. Mammals

Addition of salts and other solutes from other cells into xylem sap, __________ the water potential of the xylem sap

A. Increases.
B. Lowers.
C. Doesn’t effect.
D. Maintains.

Symbionts which help plants in uptake of phosphorous and trace metals such as zinc and copper.

A. Bacteria
B. Viruses
C. Fungi
D. Cyanobacteria

Low level of CO2 favours _________ of the stomata.

A. Opening
B. Closure
C. Both of these
D. None of these

There are _________ hypothesis which may explain opening and closing of stomata?

A. One
B. Two
C. Three
D. Four

The opening and closing of stomata is directly controlled by the___________?

A. Temperature
B. pH
C. Light
D. None of these