21. In the following diagram, nerve cell A is commu- nicating with nerve cell B. Identify the structures
present on the membranes of nerve cell B that
enable it to detect a message from nerve cell A.
26.
stre
Nerve cell A
Nerve cell B

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.

D. peatlands,grassland,swamps

Dis the