How oxygen and carbon dioxide are produced

Oxygen is produced by trees through photothnthesis and carbon dioxide is prodeced by mammals and other things breathing it out or burning fule.

c. establishing proper sleep hygiene

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: