Ionizing radiation, benzene, and certain viruses can each individually cause leukemia without the other two exposures, but only if the exposed individual has a certain genetic deficiency. This genetic deficiency by itself does not cause leukemia, but the disease never occurs in the absence of this genetic factor. The genetic deficiency is

A necessary but not sufficient cause

Explanation:

A necessary but not sufficient cause is defined as any cause/condition that is an obligate requirement for a particular event to occur (in this case, the particular event is leukemia disease), but it isn't sufficient for the occurrence of this event. Conversely, a sufficient cause is defined as any cause/condition that will cause by itself the event to occur. Finally, a condition is neither necessary nor sufficient when the condition neither is required nor sufficient for the event to occur.

tissue

explanation:

it is actually formed by geoup of cells which is tissue

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."