Earth rotates around its axis.

a. what are the effects of earth’s rotation?

b. if earth didn't rotate, what would be one major obstacle life would have to overcome?

Earth rotates around its axis are discussed below.

Explanation:

The effect of Earth's Rotation

An Imaginary line passes through the Earth's pole is called Axis.Earth spins or rotates around its axis once in a very day and this process takes 24 hours.This spinning or rotation of the earth causes Day and Night. As Earth rotates, the side we live on turns towards the Sun and causes day while the side which is opposite of the sun observe Night.And, If somehow Earth stops rotation on its axis then one side always gets day and sun heat while the opposite side never gets sunlight and becomes cooler.