What determines which bases will be brought to the DNA strand during DNA replication?

According to the big bang theory, after the "bang," the universe remained dark until about  300,000 yearsone billion yearsthree minutesthree billion years  later, when neutral atoms began to form.

3points hurry! what is the relationship between biotechnology, sharkskin, and disease resistance? bioengineers have developed an artificial sharkskin that does not allow resistant bacteria to grow on it. disease-causing microbes have been genetically modified to keep them from infecting the skins of sharks. scientists have created a device that can be attached to the skins of sharks that dramatically increases their abilities to resist disease. sharkskin produces many chemicals that can be collected and used to create antibiotics.

Is there any solid scientific evidence that humans have been cloned?