What is the function of the valves within the heart and veins? to ensure the production of blood within the body to ensure coordination of the heart cells for pumping blood to ensure that foreign materials do not enter the heart to ensure that blood flows in one direction only

to ensure that blood flows in one direction only

Explanation:

Here, we want to select which of the options is the function of valves within hearts and veins.

Basically, valves serve as control mechanisms in the circulatory system.

By control, it means that they actually dictate the direction in which the blood will flow.

Hence, valves ensures that blood types which is supposed to flow from the heart does not flow towards it and blood types that are meant to flow towards it does not flow away from it

An example of this can be seen in the case of oxygenated and deoxygenated blood.

Both have different flow mechanisms which are controlled by the actions of the valves

answer; i believe that the correct answer is(d) nondisjunction during meiosis;

yes, because even though a theory has a  lot of evidence to support it, it is not always true