Complementary base pairing in dna means that dna is easy to copy. how does this work?
a. dna isn't very easy to copy, but there's no need to do that, so it doesn't matter.
b. the base pairs that make up the center of the dna molecule will only match with identical copies of themselves a: a, c: c, etc.
c. the base pairs that make up the center of the dna molecule will only match up a with t or c with g.
d. it doesn't work very well, so many mistakes are made when dna gets copied as cells divide.
e. the base pairs that make up the center of the dna molecule match other dna molecules perfectly.

The correct answer is option C.

Explanation:

On the basis of Chargaff's rule, adenine always base pairs with thymine, and guanine always base pairs with cytosine. This rule is also called complementary base pairing. By following this rule, the DNA polymerase can produce the new strand of DNA easily.  

It utilizes the old strand of DNA as a template and produces the new one by opting for the accurate nucleotide on the basis of the template strand. Thus, the correct answer is option C, that is, the base pairs, which make up the center of the molecule of DNA will only match up C with G and A with T.  

explanation:

b,bacteria convert nitrates

into nitrogen gas.

d,plants and animals take in

and use nitrogen compounds.

e,bacteria break down waste    

products and return nitrogen  

to the soil.

a,bacteria convert atmospheric

nitrogen to ammonia.

c,bacteria convert ammonia

to nitrites and nitrates.

i would say it is