Transportation in Animals and Plants — Science STD 7 — Question

Explain how soil pollution and soil erosion could be prevented.

Rahul was a student of Class VII. His father purchased a new bicycle for him on his birthday. After few months, he found that the cycle chain and even the handle gets rusted. His father advised him to apply a coating of paint to the cycle and not to keep it in the open in future.
Now, answer the following Questions:

1. Why his cycle gets rusted?
2. What do you mean by rusting of iron?
3. What values are shown by Rahul’s father?

Explain the two mode of nutrition in plants.

One day Rahul’s mother after taking meal felt pain and irritation in her stomach. His father was out of station. Rahul was an intelligent boy. He remembered his teacher’s statement and gave his mother some baking soda solution Which gave her a relief from pain and irritation of stomach. Read the above passage and answer the following Questions.

1. Which information given by Rahul’s teacher that helped him to select the baking soda as remedy?
2. Why he selects baking soda as a cure?
3. What values are shown by Rahul?

Explain the working of human heart.

Explain the differences between self-pollination and cross-pollination.

It is not wise to sleep under a tree during night. Why?

You are provided with three test tubes A, Sand Cas shown in figure with different liquids. What will you observe when you put,

1. A piece of blue litmus paper in each test tube?
2. A piece of red litmus paper in each test tube?
3. A few drops of phenolphthalein solution to each test tube?

List the reasons for lowering of water table in cities.