Acell has a membrane potential of -100 mv (more negative inside than outside) and has 1,000 times more calcium ions outside the cell than inside. which best describes a mechanism by which ca2+ enters this cell? a. facilitated diffusion of ca2+ into the cell down its electrochemical gradientb. movement of ca2+ into the cell through an ion channel down its concentration gradientc. passive diffusion of ca2+ into the cell down its electrochemical gradientd. cotransport of ca2+ into the cell with cl-e. movement of ca2+ into the cell through a carrier protein down its electrical gradient

The correct answer is co transport of Ca2+ into the cell with Cl-.

Explanation:

When two ions are transported simultaneously across the plasma membrane through a channel protein, then this of membrane transport is called co transport.

 According to the given question the concentration of Ca2+ is 1000 times more in outside the cell than inside.

  As a result the Ca2+ ions will be transported from its high concentration region that is outside the membrane to its low concentration region that is inside the membrane.

  But the important thing to note that in every circumstances the  negative resting potential should be maintained.So to maintain the normal negative resting membrane potential same number of Cl- ion will be be transported inside the cell by co transport mechanism.

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."    

a=c and then d= c because of the band so you get ac/dc and you add them together you get sound waves