Nutrition in Plants — Science STD 7 — Question

Insects and leaves of a plant have pores through which they exchange gases with the atmosphere. Can you write two points of differences between these pores with respect to their position, number and extension into the body?

Write the difference between milk teeth and permanent teeth.

Explain the following:

1. Galvanisation.
2. Crystallisation.

A student was given a flower. He was asked to pick the different whorls of flower by the forcep. He pulled each part of the flower and laid them on the chart paper in a sequence and named them W, X, Y, Z (from outer to inner whorl). He was unable to name them.
Help the student to name the different parts of a flower. Also help him to tell which part produces male gamete and female gametes.

State the characteristics of the image formed by a plane mirror.

These students are describing some changes. What kinds of changes are they talking about?

What causes the wind to blow?

Ajay’s father works in a wool industry. In his line of work, he does the job of sorting the fleece of sheep into fibres of different qualities. Ajay noticed that his father and other workers who were doing the similar kind of jobs faced a number of health problems. Ajay discussed this problem with his friends and he came to know that his father is getting health problems due to the nature of his work. Ajay is worried about his father’s health. He advised his father to take care of their health and told him about the occupational hazards. Now answer the following Questions:

1. What do you mean by occupational hazard?
2. Name the disease that workers may at risk.
3. What values are shown by Ajay?

Discuss why wearing more layers of clothing during winter keeps us warmer than wearing just one thick piece of clothing.