Adolescence: A Stage of Growth and Change — Science STD 7 — Question

Reservoir of dam helps us to manage water. How?

How can you say that ripening of a fruit is a chemical change?

What does water cycle helps in?

Y and Z are two types of organisms which are found in the forests. Y eats up dead animals, while Z breakdown the body of the dead animals into simpler substances.
(a) What is the general name of organism Y?
(b) Write one example of Y type organism.
(c) What is general name of organism Z?
(d) Write one example of Z type organism.

Fill in the blanks using the words listed below.
water, front, intestinal, salts, pseudopodia, back, vacuole
Tongue is attached at the ___________ to the floor of the mouth cavity and is free at the ___________.

A copper wire was used in an electric circuit, and it conducted electricity well. If you replace it with a piece of coal, what will happen? Why?

Paheli observed that most of the fish in the pond of her village were gradually dying. She also observed that the waste of a factory in their village is flowing into the pond which probably caused the fish to die. If the factory waste is acidic in nature, how can it be neutralised?

Fill the missing word in the blank spaces in the following statements: Winds are generated due to __________ heating on the earth.

State whether the following statements are True or False. In case a statement is false, write the correct statement. Where underground sewerage systems and refuse disposal systems are not available, the high cost on-site sanitation system can be adopted.