Cual es la enzima que se usa en la prueba de PCR y que ayuda en la duplicación del segmento de ARN , que codifica a la proteina S del SarsCoov 2?

I’m doing some practice exam questions for biology, and i’m not sure how to do these 3 parts to the question.

Why are fossils not found in igneous rocks? igneous rocks are made from cooling of lava or magma. igneous rocks are found too deep underground. igneous rocks are too dark in color to contain fossils. igneous rocks are too dense to contain fossils.

Guinea pig coat color is determined by a single gene. the allele for black coat color is dominant to brown. in a cross between twoblack-haired guinea pigs, 20 offspring are born. if both parents were heterozygous, probability would predict that approximately howmany of the 20 offspring would have brown hair?