Which of the following is an example of active transport in a cell? Choose 1
A
Calcium passing through channel proteins, from a high to low concentration

B
Enzymes spreading evenly through cytoplasm

C
Oxygen entering the cell without the use of energy

D
Sodium moving out of the cell against its concentration gradient

How did the research presented in the article affect scientists' understanding of the evolution of eukaryotes

What is the difference between the conducting zone and the respiratory zone of the respiratory system? the conducting zone is a series of cavities and tubes that move air to the respiratory zone where gases exchange with the bloodstream. the conducting zone exchanges gases between the lungs and the alveoli and the respiratory zone is a series of cavities and tubes that move air to the conducting zone. the conducting zone moves oxygen into the cells and the respiratory zone takes carbon dioxide away from the cells. the conducting zone moves oxygen into the bloodstream and the respiratory zone takes carbon dioxide away from the bloodstream.

Nitrogen-14 and nitrogen-15 are isotopes of the same element. how do these two isotopes differ? a. they have different numbers of nuclei. b. they have different numbers of protons. c. they have different numbers of neutrons. d. they have different numbers of electrons.