Answer:
A
Explanation:
Today, the atmosphere holds about 21 per cent oxygen. ... When the first simple organisms appeared in the oceans more than 3.5 billion years ago, the atmosphere was mostly nitrogen, hydrogen, water vapor, and carbon dioxide
Answer:
Pylorus
Explanation:
The stomach is a J-shaped organ which is a part of the digestive system. The digestive system on one end is attached to the oesophagus and on the end to the small intestine.
The pylorus structure of the stomach is composed of thick muscles which help to mix or agitating the food in the stomach and controls the movement of the food to the duodenum which is the first part of the small intestine. The movement is controlled by the ring of muscles in the pylorus called pyloric sphincter.
Thus, Pylorus is the correct answer.
Answer:
B
Explanation:
We breath in oxygen, and we breath out carbon dioxide. Plants breath from the sun.
Answer:
Less energy is available to the upper trophic levels.
The very first one is the answer-
Abiotic changes have the ability to dictate biotic ones. This can be caused by humans.
For example: an abiotic thing can be an element like water. If the water in a lake gets poisoned by chemical compounds, this is an abiotic change. However, since the lake is now poisoned it’ll likely harm or even kill fish, bacteria, algae, and any other wildlife living within the lake. It doesn’t stop there though, without the lake surrounding animals won’t have clean water to drink, they can now die from either the poisoning, dehydration, or starvation if they lived off of the aquatic life from the lake.