Which factor can cause constriction in blood flow through the cardiovascular system?

a.) smoking
b.) excercise
c.) video games
d.) vegetarian diet

The circles, or orbits, for electrons are called energy levels. each level can hold only a certain number of electrons. add electrons to each level until you can't add any more. how many electrons can each level hold?

Plz quick a natural resource that is replaceable through a cycle in nature or sustainable practice is called a? the subject is science

What are the pros and cons of transect sampling?