Answer:
The Earth has three main climate zones: tropical, temperate, and polar. The climate region near the equator with warm air masses is known as tropical. In the tropical zone, the average temperature in the coldest month is 18 °C.
I'm not sure but I think it's B
Answer:
The substance moves from low to high concentration, against the concentration gradient.
Explanation:
When molecules move from high to low concentration, it is known as Diffusion. It moves with the concentration gradient and does not require energy.
However, when molecules move from low to high concentration, it is against the concentration gradient and cannot proceed without Energy. This process is called Active transport.
Cell membrane is not thick, it is thin and semi permeable.
<span>Air pollution is the presence of harmful substances in the earths atmosphere </span>
a. Competition: Humans compete with all organisms for space.
b. Parasitism: Humans have many parasites: head lice, ticks, tapeworms, etc.
c. Mutualism: We have mutualistic relationships with all domesticated plants/animals.
d. Commensalism: Pigeons thrive in metropolitan ecosystems without really
affecting humans (except for being mildly disgusting).