The contracting and relaxing of muscle is regulated by the amount of calcium present in the cells of muscle fibers. these cells must be able to move the calcium ions from areas with low concentrations to areas with high concentrations. what process would be necessary for this movement to occur? (2 points)

The right answer is active transport.

Active transport is the process of moving molecules across a cell membrane through the use of cellular energy.

The alternative to active transportation is passive transport, which uses kinetic energy to relocate only the molecules. Passive transport can only move molecules from a region of higher concentration to lower concentration, while active transport moves molecules from a lower concentration site to a higher concentration. Active transport involves molecules moving against a concentration gradient of the molecule concerned.

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."    

brain development. a child's brain undergoes an amazing period of development from birth to three—producing more than a million neural connections each second. the development of the brain is influenced by many factors, including a child's relationships, experiences and environment.

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