There are four different types of nucleotides in DNA, and they differ from one another by the type of base that is present: adenine (A), thymine (T), guanine (G), and cytosine (C). A base on one of the chains that makes up DNA is chemically bonded to a base on the other chain.
Answer:
A recessive trait is a trait that is expressed when an organism has two recessive alleles, or forms of a gene. Dominant alleles mask the effects of recessive alleles, so a recessive trait is only expressed when an organism has two recessive alleles for a gene.
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A swamp involves the biosphere and the hydrosphere
a farm involves the biosphere and the atomosphere