What substance is needed to carry out
respiration?
a oxygen
b carbon dioxide
c nitrogen
d carbon

Which part of the neuron below is indicated by the arrow, and what is its function? hormones send chemical signals throughout the body to regulate other body processes. hormones are chemical signals that are sent throughout the body to regulate other body processes. hormones send electrical signals throughout the body to regulate other body processes. hormones are electrical signals that are sent throughout the body to regulate other body processes.

As scientist had investigated evolution from a variety fields they have found

How many chromosomes are in a human gamete?