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KATRIN_1 [288]
3 years ago
8

Which describes oxygen content as Earth evolved over time? Oxygen levels sharply declined about 400 million years ago. Oxygen le

vels stay above 15 percent starting 200 million years ago Oxygen levels remain below 5 percent starting 1000 million years ago. Oxygen levels raise significantly between 1000 and 700 million years ago.
Biology
2 answers:
lora16 [44]3 years ago
5 0

Answer:

b

Explanation:

tankabanditka [31]3 years ago
4 0

the correct answer is b. i just took the quiz

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how could incoming radiant energy from the sun be affected as a result of changes in albedo in the Arctic region?
lapo4ka [179]
As albedo in the Arctic region is getting higher, incoming radiant energy of the sun will be more reflected. If albedo in the Arctic region is falling, incomig radiant of the sun will be more absorbed.
Albedo is a name of overall reflectivity in terms of the Sun's spectrum.
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3 years ago
Name to types of evidence that scientist used to support the theory of evolution?
Sergio [31]
Evidence of evolution. Scientists support the evidence of evolution because of the adaptations organisms used to have in the past compared to the present. For example, humans have organs in their bodies they don't need, but must have been used in ancient times. They can also find that humans have a common ancestor such as monkeys because of the DNA similarities and many adaptations. Hopefully this answered most of your question.
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3 years ago
What would happen if there were no abiotic factors in an ecosystem?
Brums [2.3K]

Answer:

Plants would be unable to grow and produce oxygen for the animals.

Explanation:

Sunlight, which supports plants, is considered an abiotic factor. If there were no sunlight, plants wouldn't be able to grow, which means no oxygen for many living things found in that specific ecosystem. In other words, that ecosystem would become uninhabitable.

3 0
3 years ago
Help please 20 points i mark u as brainlist
Artyom0805 [142]

Answer:

a. Mastication process and formation of bolus in the oral cavity

b. The contraction in the stomach breaks the food down into smaller pieces. These pieces are then moved to the small intestine.

c. In the small intestine, food particles are broken down into nutrients, fat, protein and carbohydrates which are absorbed into the bloodstream.

Explanation:

a. First step of digestive system functioning is the mastication process and formation of bolus in the oral cavity.

b. The contraction in stomach, with the help of digestive enzymes and acids, break the food down into smaller pieces. The small pieces of food are then released into the first part of the small intestine (duodenum).

c. In the small intestine, two enzymes released from pancreas and gall bladder break down the food particles into fats, proteins, and carbohydrates. Thereon, nutrients and carbohydrates, proteins and fats are absorbed into the bloodstream.

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Which word best explains the changes shown in these photographs?
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