Cell Structure and Functions — Science STD 8 — Question

Pahell heard her mother and her aunt talking about her cousin who is going to have a baby. They were discussing whether she would given birth to a boy or a girl. She wonders what makes the fertilised egg develop either into a boy or a girl.

Name the fuel which is used in jet aircraft engines.

Name two diseases that are caused by virus.

How does the greenhouse effect benefit Earth?

Plastic straws A and B are rubbed with dry cotton cloth. What will happen, if they are brought near each other?

What name is given to the force acting on a unit area of an object?

Name the endocrine gland which secretes hormone that maintains correct salt balance in the blood.

Will the lightning conductor still working, if it was made out of plastic instead of metal?

Which gas in the upper atmosphere prevents ultraviolet radiations of the sun from reaching the earth?

Find out the wrong statements and write them in their correct form. A brick kiln emits lot of smoke and other harmful gases causing air pollution.