according to the pedigree chart, which statement must be true?

Explanation:

As per the pedigree chart, only the males are shown as affected by the disease. Thus, it must be a sex-chromosomal inheritance, expressed in the Y chromosome or the male chromosome.  

As the females in the family are unaffected, hence the mother in the original parental generation cannot be a carrier.

It is likely that the father from the original parental generation might be the carrier.

As there are affected individuals in both the generation after the original parental generation ( the last generation having two more affected males), the statement that the chances of inheriting the decease with each successive generation is not true.

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."