Describe how the respiratory system works at the tissue level.

plz . i suck at biology

What function does the limb sever in each animal? how are the limb bones of the four animals similar? based on these similarities what can be inferred about the evolution of the four animals.

9. the history of life on earth is recorded in

1. you serve a volleyball with a mass of 2.1 kg. the ball leaves your hand with a speed of 30 m/s. the ball has energy. calculate it. 2. a baby carriage is sitting at the top of a hill that is 21 m high. the carriage with the baby weighs 12 n. the carriage has energy. calculate it. 3. a car is traveling with a velocity of 40 m/s and has a mass of 1120 kg. the car has . calculate it.