Answer:
Immune system of the body helps in fighting with the infectious agents that are foreign for the body. So the immune system protects us from infection.
When any foreign substance(antigen) comes in the body B-lymphocyte recognize it by binding the antigen through its receptor. After recognizing the antigen, B cell divides into antibody-producing plasma cell and memory cell.
Antibodies produced by plasma cells help in destroying the antigen by getting the antigen recognized by phagocytic cells or by complement activation.
B cells are antigen-presenting cell which present antigen to T cell and then T cell activates and produce chemicals that kill the antigen. Therefore the immune system has many immune cells that activate when an antigen comes in the body. This is how the immune system functions.
I the answer is C. A community is more than one individual organism or animal and a ecosystem is the study of how an organism or animal is interacting with others
What are the other choices ????
Answer:
The rate of photosynthesis increases the intensity of light or concentration of CO2 increases, however, at a certain temperature, the rate can decrease due to enzyme denaturation.
Explanation:
Photosynthesis is a unique metabolic process specific to only some organisms. The photosynthetic process, however, cannot occur without some vital ingredients including light, Carbon dioxide (CO2) and optimum temperature.
An increase in the concentration of light (from sun) and CO2 (from atmosphere) increases the rate at which photosynthesis occurs i.e. more light, CO2 results in more photosynthetic process. However, an increase in TEMPERATURE also increases the photosynthetic rate but at a particular temperature, the enzymes that bring about the photosynthetic process can be denatured or damaged, hence, at an EXCESSIVE TEMPERATURE, photosynthesis can be inhibited.
