Crews at the international space station are researching the effects of the weightlessness of space on a. human body b. cats and dogs c. other planets

A: Human Body

C is wrong because they don’t have the tools to test it on another planet

The answer is A. The human body

none, its a machine

the chart show the masses and velocities of two colliding objects that stick together after a collision.

according to the law of conservation of momentum, the momentum of the object after the collision is  

answer

1,500

kg • m/s.