Americans speak with different accents around the country. this is most likely due to
a.
the past influence of immigrants on dialect in urban areas
b.
the way language changes when spoken in isolation
c.
increasing connections between immigrant groups around the country
d.
the ways schools have taught english differently from place to place

explanation:

the sequence of amino acids in a protein determines its function. the dna sequence of a gene determines the amino acid sequence of the resulting protein. thus, any changes in dna sequence can result in changes in protein function. this is called a mutation.

the correct answer is option d.

an appositive is a noun, noun phrase or noun clause which follows another noun or noun phrase in order to describe it or name it another way. they are usually used between commas, brackets or dashes.

the example sentence with the correct use of commas is the following:

her uncle, the man over there in the red shirt, owns the hardware store in town.