Respiration in birds a) is inefficient because air only moves in one direction b)is highly efficient and ensures that air moves in multiple directions c) is highly efficient and ensures that air only moves in one direction d) is inefficient because of how air first enters into the body

Depending on the organism the number of in a cell may change

How do you know that the plant cells in these two images have different jobs, or functions? a. because all plant cells serve different functions b. because they are two different colors c. because their dna are different d. because their structures are different

Which of the following is likely not involved in this example of ecological succession? a) the rotting remains of plants add to the fertility of the soil. b)the soil becomes so fertile that eel grass is replaced by other plant species. c) the roots from plants stabilize the sediment, keeping it in place. d) the concentration of salt becomes so high that all plant life is destroyed.