Until the early _______ there were only negligible amounts of free oxygen in the atmosphere.

1 answer:

3 0

During the early earth, when photosynthesis has not yet evolved, there were only negligible amounts of free oxygen in the atmosphere. It was said that the Earth's atmosphere had no free oxygen then. This is about 3.5 billion years ago.

You might be interested in

Describe any FOUR of these major climates found in the United States and Canada: - Tundra - Subarctic - Humid Continental - Humi

Dafna1 [17]

If you have an i phone then ask siri what the question is

7 0

3 years ago

Which of the following factors helped make inland transportation and commerce possible in the United States? A. The vast mineral

deff fn [24]

The factor that helped the United States in making the inland transportation and commerce to be possible is in letter C. The intricate river system. I hope you are satisfied with my answer and feel free to ask for more if you have clarifications and questions.

7 0

4 years ago

Read 2 more answers

PORTUGAL 1 2 3 4 5 6 7

Lostsunrise [7]

Answer:

Explanation:

lol

7 0

3 years ago

1.What is the latitude of the direct(vertical) rays of the sun?

Gemiola [76]

Answer:

As explained below.

Explanation:

The sun rays reach the earth's surface at an angle of 90 degrees at the equator which is direct and is short as compared to the poles it's long and about 66.5 degrees to the south and north. In the tropics its falls as 23.5 degrees in the northern and southern hemisphere.

The sun rays that form a tangent to the northern hemisphere are at 0, 23.5, 66.5 degrees i.e tropics, temperate and poles. And same is for the southern hemisphere.

On June 21 the southern hemisphere has winter seasons as the amount of insolation that reaches the southern side is less due to the tilt of the sun.

7 0

3 years ago

Which statement best explains why scientists depend on submersibles to study ocean features?

natali 33 [55]

<u>ANSWER:</u>

The statement "the extreme pressure and freezing temperatures of the deep ocean make it dangerous to send humans to the greatest ocean depths" best explains why scientists depend on submersibles to study ocean features .

<u>EXPLANATION:</u>

The oceans are so vast and deep that humans cannot withstand the pressure in depths.

Submersibles are developed in such a manner that they can travel to the deepest parts of the ocean and study ocean life.

Submersibles are vehicles that have the capability to carry humans as well to the deep ocean floors or these can be controlled in an automatic manner.

The submersibles are provided with tools and technologies that can record ocean floor features and make their study possible.

7 0

3 years ago