NCERT Solutions for Class 8 Science for chapter 9 Reproduction in Animals

Exercises

Question-1 Explain the importance of reproduction in organisms.

Answer: Importance of reproduction in organisms is:

1. Reproduction ensures the continuity of a species.
2. It also maintains the number of individuals in a populatio
3. It is also responsible for variations in organisms in a population that help them to survive in the environment.

NCERT Solutions for Class 8 Science for chapter 2 Microorganisms Friends and Foe

Exercises

Question-1 Fill in the blanks:

a) Microorganisms can be seen with the help of a _____
b) Blue-green algae fix ____ directly from air to enhance fertility of soil.
c) Alcohol is produced with the help of ____.
d) Cholera is caused by ____

Answer:

NCERT Solutions for Class 8 Science for chapter 18 Pollution of Air and Water

Question - 1 - What are the different ways in which water gets contaminated?

Answer.

Water gets contaminated by following ways:

(1) Excessive amount of pesticides and fertilisers are being used to increase crop production. These chemicals are carried away to the water bodies by rains and floods which contaminate water.

(2) Harmful chemicals discharged from industries pollute water bodies.

NCERT Solutions for Class 8 Science for chapter 5 Coal and Petroleum

Question - 1 - What are advantages of using CNG and LPG as fuels?

Answer.

The advantages of using CNG and LPG as fuels are as follows:

(1) They can be easily transport through pipe lines.
(2) They can be used directly for burning in homes and factories.
(3) Both are clean fuels.
(4) Both CNG and LPG are used as fuel by vehicles because they are less polluting.

NCERT Solutions for Class 8 Science for chapter 3 Synthetic fibres and plastics

Question.1 Explain why some fibres are called synthetic. 

Answer.

Man-made fibres are called synthetic fibres. These fibres are prepared from petrochemicals with the help of various processes. Examples of some synthetic fibres are nylon, rayon, polyester, acrylic, etc.

Question.2 Mark (Y) the correct answer.

Rayon is different from synthetic fibres because