Getting to Know About Plants: 18 MCQs with answers

B · Autotrophs

Plants are autotrophs — they make their own food through photosynthesis. Heterotrophs must eat other organisms.

D · Chlorophyll

Chlorophyll is the green pigment in leaves that captures light energy for photosynthesis.

A · Stomata

Stomata are the tiny pores on leaves through which carbon dioxide enters and oxygen leaves.

D · Root

Roots anchor the plant in soil and absorb water and minerals, largely through root hairs.

C · Phototropism

Phototropism is the plant's response to light — shoots and leaves bend toward the light source.

A · True

Plants release oxygen during photosynthesis, which is essential for animal life, and they respire continuously day and night.

D · Xylem

Xylem carries water and dissolved minerals upward. Phloem carries food made in the leaves.

D · Phloem

Phloem is the tissue that carries glucose (food) from the leaves to the rest of the plant.

B · A seed

After fertilization, the ovule develops into a seed, while the ovary becomes the fruit.

A · Plants respire continuously, day and night

Plants respire all the time. During the day photosynthesis also runs and releases more oxygen than respiration uses.

A · Woody stem that branches near the ground

Shrubs have woody stems but branch near the ground; trees have a tall woody trunk that branches higher up.

B · Transpiration from leaves creates a suction that pulls water up

As water evaporates from leaves through stomata, it creates a pull that draws water up the xylem — like sipping through a straw.

D · Water

Germination begins when the seed absorbs water. Without water, the seed stays dormant even if other conditions are fine.

A · Both A and R are true, and R correctly explains A

The carbon in wood comes from atmospheric carbon dioxide captured during photosynthesis, so the reason directly explains the assertion.

C · A creeper

Creepers spread along the ground, while climbers need a support to grow upward. For covering bare soil, a creeper is the better choice.

B · Oxygen increases because photosynthesis outpaces respiration

In bright light, photosynthesis produces more oxygen than respiration consumes, so net oxygen rises and net carbon dioxide falls.

C · The concentration of carbon dioxide in the air

The concentration of carbon dioxide in the air is crucial for photosynthesis efficiency. A higher concentration can enhance the rate of photosynthesis, leading to increased growth, while the other factors, although important, do not directly measure the photosynthesis process.

D · Leaves arranged in a spiral pattern

A spiral pattern allows leaves to be positioned optimally for light exposure, reducing shading of each leaf and maximizing photosynthesis. The other arrangements would either block light or not utilize space effectively.