Hello There!
Before viruses can reproduce, they must infect a host cell.
Viruses need a way to enter the body before they can infect a host cell.
Answer:
air is drawn into the lungs
lungs expand
the muscles between the ribs contract to move the ribs up and down
air pressure in the chest cavity decreases
the diaphragm contracts and flattens
Eu means true therefore it is known as eubacteria
Answer:
The CTL has specific receptors that can recognize infected or damaged cells.
Explanation:
The cytotoxic T cells (CTL) is a type of white blood cells that specifically helps in destroying virus-infected cells (also damaged cells and cancer cells).
This type of cells has a special receptor called T-cells receptors (TCR) which ones recognize specific antigens (molecule that stimulate the immune systems because are “strange” to them). Virus inside a cell could bind to a special molecule called class I MHC, this molecule moves the virus to the surface of the cell where it can be recognized by a CD8+ specific antigen-receptor of the CTL.