Answer:
RNA Polymerase
Explanation:
I took a bio class last year
Answer:
B. a sequence of DNA bases that duplicates a sequence of RNA bases.
Explanation:
Transcription is the first step in gene expression. It involves copying a gene's DNA sequence to make an RNA molecule.
Answer:
Option C.
Scientist explain the incomplete fossil record because not all organisms become fossils. Processes like erosion and mountain building can change rock layers, causing fossils to be spread over multiple layers or destroyed.
Explanation:
- Fossils are the remains of organisms that are found on the rocks after they die.
- So, no one can be 100% sure about the complete fossil record because of the continuous process like erosion and other natural calamities.
- The sediment must cover any organism's remains to start the fossilization process to start. Most of the organisms start decomposing before this process can be executed.
Answer: crossing over allows for genetic variation
Explanation:
crossing over is the exchange of genes between two chromosomes which ends up resulting in non-identical chromatids that comprise the genetic material of gametes (sperm and eggs).
Basically crossing over makes the chromatids that are held together by a centromere, no longer identical to eachother which creates genetic variation.
