Answer: Partly it's because teenagers are quite different from their childhood selves. This is because the brain is continuing to mature and also because sex hormones such as testosterone, estradiol and progesterone influence brain function and these are the hormones that rise to adult concentrations at puberty.
Explanation:
Answer:
(b) increased travel of individuals from endemic regions to the United States,
<span>Organisms that have ventilation systems will draw in air (or
water) that is rich in oxygen and will draw out air that has carbon dioxide. This
is essential for a multicellular organism to thrive because carbon dioxide is
harmful for an organism since carbon dioxide (CO2) is a waste product. Such is
the system that contain veins, capillaries and arteries. On the other hand, organisms
that don’t have ventilation system, can survive without it because they are
single-celled and the path for the nutrients and needed oxygen is so short that
they can efficiently exchange gases at the surface.</span>
There are 1 to 2 called alleles