Hormones are sent throughout the system
In low light no plants grow. With no plants no animals can eat so less animals remain or stay there. With less animals less animals respire and breathe out CO2.
<u><em>Naturally acquired active immunity:</em></u> It happens when someone is exposed to a live disease and gets the disease. The person then becomes immune as a result of the first immune response.
It's sort of like a fall and learn to get up for the body.
<em><u>Artificially acquired active immunity</u></em>: It can be isert into the body by a vaccine so you won't get sick. That's why if you get a flu shot, you won't get the flu, if you get a chicken pox vaccine, you won't get the chicken pox.
It's like you're body has a personal guide telling it where and where not to step in order to not fall.
Two populations are said to be isolated if there is no longer any Gene Flow between them.
