P-2 Towards Green Energy — Science STD 10 — Question

Consider the following food chains:

1. Plants → Mice → Snakes → Hawks
2. Plants → Mice → Hawks

If energy available at the producer level in both the food chains is 100J, in which case will hawks get more energy as food and by how much? Justify your answer.

Which precautions will you take during spraying of pesticides?

What happens if there are no decomposers on the Earth?

Into which phyla is Non-chordata divided? In which three subphyla are Chordates divided?

Draw a neat labelled diagram: Hydraulic separation method.

Explain: Saving energy is the need of the hour.

When a broken piece of the stem of a plant X is planted in the soil, a new plant grows from it in a week's time. The leaves of plant X also have many small entities Y in their margins which can fall to the ground alone or alongwith leaves and grow into new plants.

1. Name a plant which X could be.
2. What are the entities Y present on the leaves of X known as?
3. Name a plant other than X which can be reproduced from its leaves.
4. Name a common plant grown in many homes which can be propagated from its broken stems like plant X.
5. Name a kind of dormant organs present in dry stems of old grass plants lying in the fields which get activated and produce green grass plants after the rains.

An organism A which cannot move from one place to another, makes a simple food B from the substances C and D available in the environment. This food is made in the presence of a green coloured substance E present in organs F in the presence of light energy in a process called G. Some of the simple food B also gets converted into a complex food H for storage purposes. The food H gives a blue-black colour with dilute iodine solution.

1. What is (i) organism A, (ii) food B and (iii) food H?
2. What are C and D?
3. Name (i) green coloured substance E, and (ii) organ F.
4. What is the process G?

Explain the meanings of the following symbols: