Viruses are particles that Select one: a. contain DNA or RNA which can be injected into a cell. b. have an exterior coat composed of protein. c. can contain an enzyme which catalyzes the reaction to make DNA from the viral RNA. d. All of these answer choices are correct.

d. All of these answer choices are correct.

Explanation:

Viruses have an exterior coat composed of protein, the capsid. Inside of it, there is DNA or RNA. When the virus has RNA, it has an enzyme that allows the synthesis of DNA from RNA. This type of virus is a retrovirus since it does the inverse process, from RNA, it gives DNA and not the other way round.

First, as the capsid has proteins, it attaches to a receptor in the cell's membrane. Then the DNA or ARN enters the cell taking it as a host since it uses the cell's structure to replicate the viral DNA and make viral proteins and DNA that then it assembles to form new viruses that will be released to infect other cells.

answer: 21

step-by-step explanation:

divide 630 by 30. 30 goes into 630 21 times

succession returns a disturbed

ecosystem to a more stable state. this is also classified into two (2) types:

primary succession and secondary succession. the primary succession arises when

a new land is transformed and a bare rock has been exposed providing an environment

that can be occupied for the first time. while, secondary succession occurs

when a previously occupied environment was disturbed that kills much of all its

community

explanation: