The process of translation involves a variety of RNA molecules, all with specific roles necessary in order to create the functional protein. mRNA (messenger RNA) is the product of DNA transcription and provides the template that the ribosome will read. rRNA (ribosomal RNA) helps create the functional ribosomal complex. tRNA (transfer RNA) brings individual amino acids to the ribosome in order to lengthen the growing polypeptide chain.

The genetic code is defined as being both unambiguous and degenerative. The term degenerative means that an amino acid can have multiple codons that code for it. For example, both UCC and UCG code for the amino acid serine. The term unambiguous means that a codon will always code for only one amino acid. For example, UCC will only ever code for serine; it cannot generate any other amino acid.

Each codon has three nitrogenous base units. Since there are four possible bases, there are 64 3-base combinations (64 possible codons). The degenerative nature of the code allow each and every combination to code for an amino acid.

The central dogma of molecular biology states that DNA is transcribed into RNA, which is then translated into protein.

The central dogma describes the flow of information from genes to a final protein. Initially, information is coded within DNA. During transcription, this information is transferred to RNA molecules. The RNA molecules are then transcribed to create functional proteins.

The correct sequence is: DNA  RNA  Proteins

Note that enzymes are a particular type of protein. Though enzymes can help with transcription and translation, they are not considered an independent step in the central dogma and fall under the more general category of "proteins."

In the case of the giraffe, chameleon, and rose, the species naturally adapted in order to survive. However, in the case of the dogs, there was intervention by man. Certain species and individuals were crossed to select for the desired genes that result in hypoallergenic fur, allowing the dogs to be kept by owners who would otherwise be allergic. Therefore, the dogs are an example of ARTIFICIAL selection, while the other choices demonstrate NATURAL selection. Natural selection is also referred to as survival of the fittest.

Natural selection is when nature makes certain traits more common due to their inherent advantage in a given environment. When a prairie dog is better hidden based on its fur color, that color will become more common over time as the darker fur colors are eaten away by predators. Humans can also make certain traits more common over time, such as in dogs, but this is an example of artificial selection, not natural.

Alleles are different forms of the same gene. For example, the gene for flower color in a plant may come in two allele varieties: white or purple. Both alleles code for flower color (the same gene), but represent different types of the genetic expression.

Humans are diploid organisms, meaning that they carry two alleles for each gene, one from each parent. Organisms with two copies of the same allele are considered homozygous, while those with copies of two different alleles are considered heterozygous.

When an organism has only one type of allele for a given gene, it is described as homozygous ("homo-" meaning one). Organisms can be either homozygous dominant, meaning they have two dominant alleles, or homozygous recessive, meaning they have two recessive alleles.

A heterozygote, or hybrid, has two different types of alleles for a given gene. When the dominant allele causes the recessive trait not to be represented in the phenotype, the organism is considered a carrier for the recessive trait.

There are a variety of mutations that can affect how a protein product is made in the body. Of the options listed, a silent mutation is the only type that does not change the final protein product. In a silent mutation, the DNA sequence is changed, but the amino acid product remains the same. Because there is no change in functionality, a silent mutation cannot harm the organism.

All of the other types of mutations listed will change what the final protein looks like, and can affect the organism in a negative way.

Nonsense mutations alter the position of the stop codon in the mRNA strand, which creates a different product. The result is a shorter polypeptide chain that may not be able to function.

Silent mutations do not alter the final protein product. A missense mutation causes an amino acid to be replaced by another, different amino acid. A frameshift mutation changes how the mRNA strand is read by the ribosome, resulting in a dramatically different product.