Answer:
Minors
Explanation:
because she's under the age of 18 and it 21 in some states
<span>Similarly to cells, viruses can spread and grow, as well as mutate. They can change what they do becoming even more deadly or they can become immune to medicine. They can also spread from cell to cell, then from people to people, change the way they spread as they mutate, and many many other things that are usually bad for humans.</span>
Answer: Valves in the veins
Explanation: The flow of the blood inside the body takes place through the veins and arteries. The oxygenated blood from the heart is supplied to the different parts of the body.
The blood flows from the capillaries to the venules and from there to the veins. The blood moves in the veins by the rhythmic movement of the smooth muscles in the body.
Most of the blood moves against the gravity so there is a chance that it can backflow so to prevent this there are valves in the veins known as one way valves.
Development of the ozone layer
>> sharks and trilobites abundant in oceans
>> plants and animals colonize land
>> dominance of reptiles >> dominance of mammals
