Answer:
peptide antigens by MHC class II molecules
Explanation:
Helper T cells are activated by peptide antigens by MHC class II molecules. These antigens express on the surface of antigen-presenting cells (APCs). After activation, the T helper cells divide and secrete cytokines to assist the immune response.
Answer:
We can immediately cross-out C
We can also cross-out A.
Now we have B and D. Commensalism and Mutualism. Now, commensalism is an association between two organisms in which one benefits and the other derives neither benefit nor harm.
Mutualism is the doctrine that mutual dependence is necessary to social well-being.
I would say D: Commensalism. Both fish can survive without each other.
The reason that might cause a reaction that originally proceeds through the path of X to change and proceed through the path Y is the addition of a catalyst.
<h3>What is a catalyst?</h3>
A catalyst is a substance that provides an alternative path for reaction. This implies that the energy tat s required to surmount the energy hump as the reactants are converted into products have been reduced. This can be seen in the fact that the energy hump between the reactants and the products in Y is lower than that in X
Thus, we could say that the reason that might cause a reaction that originally proceeds through the path of X to change and proceed through the path Y is the addition of a catalyst. The catalyst lowers the activation energy of the reaction.
Learn more about catalyst:brainly.com/question/12260131
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The body is to could to function properly and has to spend all it energy on trying to keep you warm
Answer:
Leukocytes are also called white blood cells. These cells have a nucleus, unlike red blood cells that lack a nucleus. Also unlike red blood cells, white blood cells do not contain hemoglobin, which means they're not involved in the transport of oxygen.
