1. which statement most accurately describes the process of respiration?
select one:
a. it occurs only in plants during the daylight hours and usually involves the exchange of gases.
b. it occurs only in plants during the daylight hours and involves the taking in of preformed organic molecules.
c. it occurs continuously in the cells of all organisms and involves the synthesis of carbohydrate molecules.
d. it occurs continuously in the cells of all organisms and often involves an exchange of gases.

this transfer is call conjunction

oxygen is the first element in group 16 (via) of the periodic table. the periodic table is a chart that shows how chemical elements are related to each other. the elements in group 16 are said to belong to the chalcogen family. other elements in this group include  sulfur, selenium, tellurium,  and  polonium.  the name chalcogen comes from the greek word  chalkos,  meaning "ore." the first two members of the family, oxygen and sulfur, are found in most ores.

oxygen is by far the most abundant element in the earth's crust. nearly half of all the atoms in the earth are oxygen atoms. oxygen also makes up about one-fifth of the earth's atmosphere. nearly 90 percent of the weight of the oceans is due to oxygen. in addition, oxygen is thought to be the third most abundant element in the universe and in the solar system.