Explain how an ecosystem that has experienced a disruptive event, such as a volcano, recovers.

An ecosystem can recover from even the most devastating events such as volcano eruptions. For instance, it has been observed that after the eruption of Mount Saint Helens, all of the plant life lay waste. However, and contrary to scientists' forecasts, majority of thee plant life began to grow anew in the wastelands after the eruption. Furthermore, animals from outside the region began to transfer to the area starting with airborne insects, herbivores and the rest respectively. 

This was not an isolated case, and has been found in places like Mt. Rainier &  Mt. Fuji. These recoveries give us a glimpse of the ecosystem's even to the most harsh conditions.

Ithink the answer is d.

When a virus infects a host cell, it uses the cell's machinery to make copies of its own genetic material in a process called replication. finally, during the process of self-assembly, that protein shell and the copies of the virus's genetic material are assembled into new viruses.