A. Write two sentences explaining how carbon returns from the air to the ground. ​

In the atmosphere, carbon is attached to oxygen in a gas which is called carbon dioxide and through the the process of photosynthesis, it is pulled from the air to produce food made from carbon for plant growth. And through food chains, the animals that eat plants get that carbon and so do the animals that eat those animals.

When an animal dies, their bodies as well as wood and leaves decaying brings the carbon into the ground.

in the year 2850, humans successfully colonized mars. the martian modules that were constructed could hold only a small population of people. it is now a century later, and the population on mars has grown to 600 people. of the current mars population, 45 people express the recessive phenotype for phenylketon- uria (pku) syndrome (pp genotype).

explanation:

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