The primary difficulty is the fact that we do not know all of the organisms that currently exist in the world along with those that existed in the past.
The answer is c it's the best one
Answer:
Innate immunity is a non-specific immune system which provides defence against any pathogenic microorganism in early stages. It includes physical barrier such as skin, chemical barriers such as saliva, tears, et cetera, phagocytic cells such as macrophages, et cetera.
Acquired immune system is the one which develops after exposure to pathogen or antigen. It is highly specific in nature. It includes B-lymphocytes and T-lymphocytes. It includes the production of antibodies.
Vaccines are used to develop acquired immunity in people. The process is termed as vaccination or immunisation. Heat-killed or weakened pathogen or antigen is inserted into a person after which a person develops antibodies and memory cells against that pathogen or disease. So, the immune system acts more vigorously against that pathogen in secondary infection.
Thus, a person becomes immunised.
QUICK ANSWER
A combination of sand, salt and water is an example of a heterogeneous mixture. A heterogeneous mixture is a type of combination where the constituents of the mixture are not uniform, and there are two or more distinctive phases of separation.
Answer:
C). Buffers
Explanation:
The given analogy can best be completed with 'buffers' as it similarly compares with the 'solution pH' like the comparison between 'shock absorbers' and 'vehicle movement.' <u><em>Like the 'shock absorbers' function to help in improvising the vehicle movement and ride quality by lowering the effect reverberations of traveling on a rough platform, similarly, the 'buffers' help in regulating the 'pH of a solution.</em></u>' Thus, <u>option C</u> is the correct answer.
