Questions

Savannas are home to a wide diversity of animals.

Many animals of the savanna migrate throughout the year, searching for food and water. Many of the droughts are seasonal and hit one area before another, so animals are constantly following the rains.

Hence, Rain fall is what often governs animal migration on savannas.

The weight of the man mg is acting on the floor. As the lift is moving up with an acceleration, say a, the man too in it is having this acceleration. The force producing this acceleration is ma. By Newton's third law, this force will have an equal reaction pressing the floor equal to ma. Therefore the total resultant reaction on the floor is mg+ma = m(g+a) which is mg, the weight of the man. So (a) is correct.