Electric Current and its Effects — Science STD 7 — Question

Why do we often sneeze when we inhale a lot of dust-laden air?

The Indian cricket team matches in Australia are often held in December. Should they pack winter or summer clothes for their trip?

In which layer of the soil would you find humus? What is its importance to the soil?

Could the light from the Sun get blocked by the two planets which are revolving between the Earth and the Sun?

Explain what do you understand by sexual reproduction?

Insects and leaves of plant have pores through which they exchange gases with the atmosphere. Can you write two points of difference between these pores with respect to their position, number and extension into the body?

Explain with examples how animals have adapted themselves to overcome the competition for food and shelter in the rainforests.

We should avoid taking medicines/drugs unless prescribed by a doctor. Give reasons.

Why is it necessary to excrete waste products?

How did early humans measure time before clocks?