Answer:
Explanation:
1) Excitation brings about contraction.
2) Contraction leads to an increase in blood pressure.
3) Changes in blood pressure results in the opening and closing of the heart valves.
4) The opening and closing of heart valves then regulates the flow of blood and it's volume.
Answer:
Land use goes up as human population goes up. This is because the more people there are alive, the more land that people will be using. Hope this helps :)
4 i guess........................
<span>Answer: 1/4 AA or type A Blood; 1/4 BB or type B Blood; 1/2 AB</span>
Since IDK which two you would choose, I'll just list all of them: fish have developed a light, streamlined body to get through water quickly to evade predators with and swim with ease, owls have big eyes so their pupils can get enough light to see in the dark since they're nocturnal, their light bodies and special (Fluffy???) flight feathers let it fly with virtually no sound, allowing it to sneak up on prey, tortoises have a large, hard shell for protection from predators and provides a mobile home on their back! Bats may be practically blind but that doesn't stop them when using echolocation to detect prey and chase it no matter what moves they make or obstacles in the way, snowshoe hares have big feet to sit on top of the snow in the cold winters where they live, their fur also changes colors as the snow melts and the plants start coming back in the more warmer seasons, poison dart frogs, sorry, IDK, cacti have developed spines all over them as self defense, (from what IDK) and they can last a long time without water (I think, don't quote me on that ^^') hope this helps
