The core of the immune system is made up of red blood cells.

platelets.

white blood cells.

intact skin.

intact mucus membranes.

red blood cells

Explanation:

white blood cells are used for fighting against diseases

thinking it would be d not too sure but i think it's right

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: