Read the following statements that describe an hiv infection. what is the correct order in which they occur?

1) reverse transcriptase uses viral rna as a template to make viral dna.
2) virus coat fuses with cell membrane and viral rna enters the cell.
3) virus attaches to host cell membrane.
4) the new viruses bud off from the host cell membrane.
5) viral dna enters nucleus and inserts itself into host dna.
6) viral mrna directs the host cell to assemble viral proteins.

choices:

a. 2,3,6,1,5,4

b. 2,3,1,5,6,4

c. 3,2,1,6,5,4

d. 3,2,1,5,6,4

The correct answer is -

D. 3,2,1,5,6,4

Explanation:

Infection of HIV (human immuno deficiency virus) into the host cell primarily involves the following steps-

1) Binding of virus to host cell,

2) Fusion of viral coat to host cell membrane so that entry of virus takes place.

3) Action of reverse transcriptase enzyme to make viral DNA from viral RNA,

4) Integration of viral DNA into host genome,

5) Replication of viral genome along with host genome.

6) Assembly of viral particles through viral mRNA (formed through transcription).

7) Budding of new viral particles from the membrane.

According to this sequence, option D) is the right answer.

from my research i have to the conclusion that decomposers, such as fungi, bacteria and invertebrates, play a critical role in nutrient cycling and without them the earth's ecosystem may not support life as we know it. elements such as carbon, nitrogen and phosphorus exist in limited amounts on earth, although huge amounts of carbon are being released into the atmosphere from underground sources now by humans. it is still extremely important that other nutrients be retained by the process of re-use. decomposers are organisms that are able to chemically break down dead material and make these elements available for use by other organisms. without this breakdown of dead material, dead bodies would pile up. so decomposers also play a role in clean up also. without them, life might not continue as we know it and dead material would overwhelm the earth.    

it is a learned trait

explanation: