Solved MCQs of Biology Class 9 Chapter 9

Valves to prevent the backflow of blood are found in the:

Arteries

Veins

Capillaries

All of the above

Platelets life span in about ……….. days.

6-7

7-8

5-6

8-9

Which of these are responsible for blood clotting?

Platelets

Erythrocytes

Neutrophils

Baseophils

Plasma contains ……………… % water.

10%

7%

90%

2%

Which of the following contains deoxygenated blood in an adult human?

Left atrium

Pulmonary artery

Pulmonary vein

All of the above

……………. is the first organ which comes out of seed.

Stem

Root

Leaf

All

In experiments to show transpiration from lead surfaces cobalt chloride paper changes its colour from:

Pink to blue

Blue to pink

Pink to colourless

Colourless to pink

Stomata close when the guard cells;

Lose water

Gain chloride ions

Became turgid

Gain potassium ions

Which of the followings in not true about the opening and Closing of Stomata?

Light helps in the opening and closing of stomata

K+ ions are responsible for the opening and closing of stomata

The osmosis of water is responsible for the opening and closing of stomata

None for these

Heart consists of ………… chambers.

Two

Three

Four

Five