When babies are born, their brains contain about a hundred billion of neurons. However, a few of these brain cells are connected. At age three, there are one thousand trillion connections formed. The brain starts to cut off unused connections at the age of eleven.
Answer: The correct answer is option C
FACILITATED DIFFUSION.
Explanation: FACILITATED DIFFUSION is a form of passive transport,it is the process by which substances(molecules) move from a region of higher concentration to a region if lower concentration along their concentration gradient through the help of a membrane transporter forming a pore or channel(Protein).
Facilitated diffusion dies not require high energy to occur since a concentration gradient is involved.
The answers could be vasodilation and vasoconstriction (respectively) if that’s what u are studying.