answer.
Ask question
Login Signup
Ask question
All categories
  • English
  • Mathematics
  • Social Studies
  • Business
  • History
  • Health
  • Geography
  • Biology
  • Physics
  • Chemistry
  • Computers and Technology
  • Arts
  • World Languages
  • Spanish
  • French
  • German
  • Advanced Placement (AP)
  • SAT
  • Medicine
  • Law
  • Engineering
KATRIN_1 [288]
2 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]2 years ago
5 0

Answer:

b

Explanation:

tankabanditka [31]2 years ago
4 0

the correct answer is b. i just took the quiz

You might be interested in
Iodine is a yellowish solution. A starch solution is white. A starch solution turns purplish-black in the presence of iodine. If
cupoosta [38]

Answer:

The correct answer will be- the color change will be observed and the solution will turn purplish-black.

Explanation:

Iodine test is performed to test the presence of the carbohydrates mainly starch.

The iodine solution is chemically called potassium iodide which forms a yellow solution. The potassium iodide solution forms a complex with a starch solution which appears a purplish-black color which shows the presence of the carbohydrates.

In the given question, if we add the iodine solution to the beaker after a certain point of time then it will still form a complex with the starch and thus beaker solution will appear darker in color.

6 0
2 years ago
Even though plants cells photosynthesize, they still use their mitochondria for oxidation of pyruvate. This will occur in _____.
lidiya [134]

Answer:

All cells all the time.

Explanation:

Photosynthesis is the process of the formation of organic nutrients, glucose in the presence of sunlight by fixing CO2. Cellular respiration is the oxidation of nutrients. The process forms ATP which in turn serve as energy currency for living cells.  

Plant cells perform cellular respiration to obtain the energy stored in the chemical bonds of glucose. The energy obtained by cellular respiration is used to perform the vital functions by cells. Therefore, irrespective of photosynthesis, cellular respiration occurs in all the cells of the plants all the time to fulfill the energy requirement for growth and development.

7 0
2 years ago
Students investigated samples of amylase from 100 goats. 100 small filter paper discs were each soaked in a different sample of
Korolek [52]

This question is not complete

Complete Question:

Students investigated samples of amylase from 100 goats. 100 small filter paper discs were each soaked in a different sample of goat amylase. The students tested the activity of these amlyase samples using plain paper. Plain paper contains starch.

A circle of plain paper was placed into a Petri dish ad shown in the diagram below. Iodine solution was used to stain the starch in the plain paper.

When iodine solution reacts with the starch in the plain paper, what colour would you see?

Answer:

The colour that would be seen is blue black .

Explanation:

Amylase is an enzyme that is involved in the breaking down or hydrolyses of starch.

When Amylase reacts with iodine, it speeds up the rate of reaction of the hydrolysis of the starch present in the plain paper.

The colour that would be observed is a blue black colour and the starch in the paper would be broken down further more into simpler sugars.

4 0
2 years ago
Read 2 more answers
Henry bought 280 red and blue paper cups. He used of the blue
stellarik [79]

Answer:didn’t put the number for how many blue cups were used

Explanation:

6 0
2 years ago
What is the difference between a harmful helpful and neutral mutation
s2008m [1.1K]
A harmful mutation will harm the organism, a helpful will help the organism to survive, and a neutral will not affect the organism.Lol I feel like a nerd
8 0
2 years ago
Read 2 more answers
Other questions:
  • Saki went on vacation and was fortunate enough to get to see the aurora australis. What solar activity did she observe? solar fl
    14·2 answers
  • Lipase, maltase, and protease are members of a group of catalysts known as
    15·1 answer
  • You have reached a final decision: you are going to create a new lunch program that will include healthier foods. List one benef
    9·3 answers
  • Does increasing the size of an axial substituent always result in higher relative strain energies for the axial conformation
    5·2 answers
  • Which statement describes ozone?
    14·2 answers
  • 25] Discuss what your analysis above indicates about the applicability of the Hardy-Weinberg criteria to this population. Which
    5·1 answer
  • What is the significance of study human biology in understanding cultural capacity? Explain your answer with atleast 1 paragraph
    7·1 answer
  • Explain why leaves often contain starch​
    10·1 answer
  • How did Claire’s digestion reaction rates tell you that the problem was in her small intestine, and not her stomach?
    5·1 answer
  • Sally is a 41 year old female with a history of unsuccessful weight loss attempts. In the past, Sally has tried "almost every di
    12·1 answer
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!