Answer: Option B) Antigens
Blood typing is based on the presence of proteins known as antigens on the outer surface of the red blood cell plasma membrane.
Explanation:
Blood groups A, B, AB, and O are determined based on the antigen-antibody reactions between donor and recipient bloods.
For instance,
- Blood type A has antigen A on its plasma membrane
- Blood type B has antigen B on its plasma membrane
- Blood type AB has both antigen A and antigen B on its plasma membrane
- while blood type O has neither antigen A nor B on its plasma membrane
So, antigens is the answer
Answer:

aka Ethenone
Explanation:
Ethenone is an organic compound made out of the elements Carbon, Hydrogen, and Oxygen. It is an example of a covalent molecule. The Hydrogens are single bonded to the carbon and then the carbons and oxygen are double-bonded to each other. Additionally, because there are 2 Hydrogens and 1 Oxygen the ratio is 2:1, as stated in the question.
Answer:
BS is caused by the increasing use of air conditioning in modern offices, leading to bacteria build-up in the ventilation systems. Using UV lights to fight SBS is effective since it is easy and cheap to install, and it could save companies money in reducing the rate of sickness in the employees.
Explanation:
10 is D. Unfortunately, I do not know number 9 sorry