Describe the different types of membrane transport and how they relate to concentration gradients and energy.

Two main types of active transport are:

Passive transport: The membrane transport that do not require the expense of energy for the transportation of molecules. The molecules are transported along the concentration gradient across the membrane. Passive transport includes osmosis, simple diffusion and facilitated diffusion.

Active transport: The membrane transport that requires the expense of energy in the form of ATP for the transportation of molecules. The molecules are transported against the concentration gradient across the membrane. Active transport includes direct or primary active transport and secondary active transport.

4.) metal

"-the movement of carbon from the nonliving environment into living things and back to the environment

-carbon is the essential component of proteins, fats, and carbohydrates (which make up all organisms)

-carbon exists in air, water, and living organisms

-producers convert carbon dioxide in the atmosphere into carbohydrates during photosynthesis

-bacteria in the atmosphere cycles through the system in filtration units

-in cellular respiration, carbon is released back into the atmosphere as carbon dioxide

-some carbon is stored in limestone (forming one of the largest "carbon sinks" on earth)

-largest carbon reservoir on earth= limestone

-carbon stored in the bodies of organisms as fat, oils, or other molecules may be released into the soil or air when the organism dies

-this may form deposits of coal, oil, or natural gas (fossil fuels, which increased the atmospheric carbon dioxide)

-fossil fuels store carbon left over from bodies of organisms that died millions of years ago

-they are located in the surface of earth, deep within the earth and beneath the ocean floor."    

option c is the correct answer.