Are responsible primarily for regulating sexual activity, socializing children, and providing affection and companionship for members.a. preindustrial familiesb. agricultural familiesc. hunting and gathering familiesd. contemporary families

Option D, Contemporary families

Explanation:

In a contemporary societies , families become part of social change and they also try to change with time. They adopt all the changes that are intended towards the growth and advancement of the educational and professional standards so that the overall impact on the family and its function increase,

These families take the overall responsibility of upbringing of children inclusive of their sexual and marriage life. These families have a better standard of living and thus they are able to dedicate more love, care and attention to their children

Hence, option D is correct

Nucleotide bases.

Explanation:

Unique sequences of bases makes up a nucleotide. These nucleotide sequencing are used by DNA as a genetic code of information that determines type of cells, proteins and the whole organismal structure.

There are four nucleotide bases, Adenine and guanine termed purines are big, cytosine and thymine called pyrimidines are small. A purine pairs with a pyrimidine, such that adenine pairs with thymine and guanine pairs with cytosine. The bases are the same but each DNA uniqueness lies in the sequence of base pairing.