You toss a ball to a friend. When the ball reaches its maximum ...

[asan beg]

You toss a ball to a friend. When the ball reaches its maximum altitude, its acceleration
 
  A) changes sign.
  B) is zero.
  C) is constant.
  D) is g/2.
  E) is 2g.

Question 2

A habitable zone
 
  A) exists around all stars
  B) only exists around stars which are identical to the Sun
  C) only exists around stars which are similar to our Sun
  D) only exists around one star, the Sun

[chereeb]

Answer to Question 1

C

Answer to Question 2

A