Answer: Antigens
Explanation: The ABO system of blood grouping is based on the basis of the type of antigens that are present in the red blood cells. Erythrocytes is another name for the red blood cells. Antigens are molecules that are capable of eliciting immune response. There are two types of antigens: antigen A and B. Blood type A has only antigen A, blood type B has only antigen B, blood type AB has both antigen A and B while blood type O has no antigen (neither A nor B antigen).
Similarly, Rh trait is determined by the presence or absence of rhesus antigen in the erythrocytes. Rhesus antigen is an antigen first discovered in rhesus monkey. Rh+ indicates the presence of rhesus antigen in the red blood cells while Rh- indicates the absence of rhesus antigen in the red blood cells.
The answer to this question would be D (DNA). It can be found in the nucleus of a cell and contains the entire genetic information of a whole.
Answer:
we itch reacting to stimuli like when ee get poked we react and so on. And it not an evolution
Answer: B
Explanation:
Ammonia is so toxic that it can be transported and excreted only in large volumes of very dilute solution. As a result most terrestrial animals simply don't have access to sufficient water to routine excrete ammonia.
The main advantage of urea is its very low toxicity. Animals can transport urea in the circulatory system and store it safely in high concentrations. Also much less water is loss when a given quantity of nitrogen is excreted in a concentrated solution of urea than would be in a dilute solution of ammonia.
Protozoans, bacteria, fungi... viruses are not organisms
