Choose the correct option from the following:

Which part of the plant takes in carbon dioxide from the air for photosynthesis?

• (i) Root hair

• (ii) Stomata

• (iii) Leaf veins

• (iv) Petals

Green plants are called _________________ since they synthesise their own food.

How would you test the presence of starch in leaves?

Answer explanation

Solution:

Take two potted plants of the same kind. Keep one in the dark for 72 hours and the other in the sunlight. Perform the iodine test with the leaves of both plants as given below. Now, leave the pot, which was earlier kept in the dark, undisturbed for 3–4 days and perform the iodine test again on its leaves.

Iodine test:

Put iodine solution on the leaf.

Observation:

Blue-black colour will be observed on the leaves of the plant kept in sunlight, which indicates the presence of starch.

Blue-black colour will not be observed on the leaves of plants kept in the darkroom. This indicates the absence of starch.

Draw a diagram of stomatal opening.

Name the following.

A parasitic plant with a yellow, slender and branched stem.

Give a brief description of the process of photosynthesis of food in green plants.

Answer explanation

Solution:

Green plants use a process called photosynthesis to prepare their food. The process is as follows

• Water is taken from the roots of the plant, and it is transported to the leaves of the plant.

• Carbon dioxide from the air enters the leaves through pores called stomata. This diffuses the cell containing chlorophyll.

• Water molecule is broken down into Hydrogen and Oxygen with the help of sunlight.

• Hydrogen combines with Oxygen and Hydrogen to form carbohydrates.

• Photosynthesis is represented by the following equation.

Why is light very important to plants?

Answer explanation

Light is so important to plants that their leaves grow in many patterns so as to absorb maximum sunlight.

How are nutrients replenished from the soil?

Answer explanation

Solution:

Nutrients can be replenished in the following ways: Fertilizers and manures contain plant nutrients such as nitrogen, phosphorous and potassium, etc. So, when fertilizers and manures are added to the soil in the fields, then the soil gets enriched with nutrients like nitrogen, phosphorous and potassium, etc.

How does fungi acquire nutrients?

Answer explanation

Solution:

Fungi get their nutrition by absorbing organic compounds from the environment. Fungi are heterotrophic: they rely solely on carbon obtained from other organisms for their metabolism and nutrition.

During photosynthesis, plants take in ______________________ and release __________________ gas.