Answer: It's not blocked
https://www.khanacademy.org/science/high-school-biology/hs-human-body-systems/hs-body-structure-and-homeostasis/a/tissues-organs-organ-systems
Diffusion is defined as the movement of particles from higher concentration area to lower concentration areas. It continues until the concentration of substances is uniform throughout.
So, the best possible answer to this question is option A - when you inhale oxygen into your lungs,it is sent through your bloodstream to the rest of your body.
<span>Conservation efforts
It is true that conservation efforts have resulted in restoration of some wildlife habitats. Since some animals, over the change of time and of human’s abusive efforts, could no longer live, the governmental an non-governmental organizations and volunteers are now doing ways to alleviate the said problem and so far it has been effective as som species close to extinction was saved (e.g. platypus).</span>
Its known as the "master gland"
Hope this helps!
