If a machine has 100% efficiency, it means that
output work is equal to input work.
% output force is equal to input force.
output work is twice the input work.
output force is twice the input force.

The two tubes contain bromothymol blue. after 24 hours, what will the color of the water be in tube b? a. green (it won't change) b. yellow c. blue d. colorless (clear)

What two factors does carrying capacity compare? population size and resource use population growth and resource availability resource use and time population size and time

Where is having brightly colored feathers that attract mates most clearly an adaptation for a bird? a. a forest with dense vegetation b. a sandy beach beside an ocean c. a snowy tundra with little vegetation d. a swamp with many hawks that eat birds