my answer for these are 1. a 2.c 3 d but not sure so please anyone see if i am correct

Question

1. In which of the following cases is work done on the object?
A. Lifting an object off the floor.
B. Pushing an object, but it does not move
C. Carrying an object at a constant velocity
D. None of these

2. The energy of a system increases when
A. a force is applied to it
B. it does work on the environment
C. The environment does work on it.
D. None of these

3. The energy of a system decreases when
A. it does work on the environment
B. a force is applied to it
C. the environment doe work on it
D. none of these

Answer 1

Iwould go 3A. Others right.