Organs
only exist in animals.
are less complex than the tissues which make them.
perform functions that tissues cannot carry out on their own.
are made of only one type of tissue.

answer: c

explanation:

the nitrogen cycle provides nitrogen to the ecosystem from the atmosphere, ground and oceans. nitrogen is an important component of complex molecules such as amino acids and nucleotides, which lead to the creation of proteins and dna, the building blocks of all life. plants absorb nitrogen in the form of ammonium, nitrate ion and, on rare occasions, as amino acids. animals receive nitrogen necessary for biological processes from feeding on living or dead organic matter.

some inherited genetic mutations can be good for the offspring, so the answer is different genetic mutations cause many forms of cancer.