Q.4 Answer the following questions in very short.
1. Give an example of natural change.
2. Are physical changes irreversible?
3. Define stimulus.
4. Which method is used to cover the wooden wheels of bullock cart with iron rims?
5. Define cell.
6. Name the living thing that are called autotrophs.
Answers
Answer 1
Examples of natural changes are growth in man and seasonal changes
Answer 2
A physical change is a change to a sample of matter in which some properties of the material change, but the identity of the matter does not. ... Physical changes can further be classified as reversible or irreversible. The melted ice cube may be refrozen, so melting i
Answer 3
A Stimulus (plural stimuli) is something which causes a response. It is used in various bodies.
Answer 4
Heating. The wooden wheels of a bullock cart are covered with iron rims by heating them in the first place as they get expanded upon heating. They are then cooled down rapidly so that they easily fit on to the wheel.
Answer 5
Cells are the basic building blocks of all living things. The human body is composed of trillions of cells. ... Cells have many parts, each with a different function. Some of these parts, called organelles, are specialized structures that perform certain tasks within the cell.
Answer 6
Algae, along with plants and some bacteria and fungi, are autotrophs. Autotrophs are the producers in the food chain, meaning they create their own nutrients and energy. Kelp, like most autotrophs, creates energy through a process called photosynthesis.