Matter in Our Surroundings — Science STD 9 — Question

Name the class in which:

1. Digits end up in nail and claws.
2. Hair are present as exoskeleton.

On the earth, a stone is thrown from a height in a direction parallel to the earth’s surface while another stone is simultaneously dropped from the same height. Which stone would reach the ground first and why?

What are boutons?

A plastic ball and a clay ball of equal masses, travelling in the same direction with equal speeds, strike against a vertical wall. From which ball does the wall receive a greater amount of momentum?

Name the cells that are dead and have no intercellular spaces.

Why are striated muscles called skeletal muscles?

Give the formulae of the compounds formed from the following set of element: Nitrogen and magnesium.

Food grown on organic farming principles is called ______ food.

What is the direction of air in coastal areas during the night?