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In the atmosphere of the primitive earth there was no ________

In the atmosphere of the primitive earth there was no ________ Correct Answer Oxygen

For decades, scientists believed that the atmosphere of early Earth was highly reduced, meaning that oxygen was greatly limited. By 2.7 billion years ago, a new kind of life had established itself: photosynthetic microbes called cyanobacteria, which were capable of using the Sun's energy to convert carbon dioxide and water into food with oxygen gas as a waste product.

Related Questions

The moon looks blood red during a total lunar eclipse because some of the sunlight passes through Earth’s atmosphere to reach the moon. As the white light breaks up while passing through the atmosphere, most of its blue-colored wavelengths are absorbed and scattered. The remaining red wavelengths light up the moon in blood-red color. Which of the following statements do not support the assertion of the above-given statement? I: The moon looks blood red during a total lunar eclipse as the white light breaks up due to the Earth's atmosphere where most of its red-colored wavelengths are absorbed. II: The moon looks blood red during a total lunar eclipse as the earth blocks the white light to travel to the moon.
The phases of the moon as we see from the Earth are due to changing relative positions of the sun, the earth and the moon. Which of the following statements is true. A. on a full moon day, the earth comes between the sun and the moon B. on a new moon day, the moon is in between the earth and the sun C. on a full moon day, the moon is in between the earth and the sun D. on a new moon day, the earth is between the sun and the moon? E. on a new moon day, the sun is between the moon and the earth
Which of the following statements are true about water available on earth? A. Only about three percent of total water in earth is fresh water B. Oceans possess 90 percent of the total water on earth C. Water on earth is created fresh from atmosphere D. Glaciers, rivers, springs and ponds are sources of fresh water Choose the correct option.
Which of these statements are correct regarding the atmosphere of the earth:
1. It is enveloping the earth because of gravity.
2. Its density decreases with increasing height from the surface of the earth.
3. Its characteristic composition is same throughout its height.
4. Amount of pressure it exerts on earth's surface at sea level is called one atm sphere.
Consider the following statements of Kupier (1949, 1951) and choose the correct answer:
1. A part of a huge cloud of dust and gas condensed to form primarily a proto-sun of low density surrounded by a rotating cloud disk
2. The proto-earth probably was a low-temperature body of gases and solids of about 500 times the earth's present mass
3. The accumulation of cold solid, the planetesimals, is the main process in the formation of primitive earth
4. The size of the planetesimals ranged in between the size of asteroids and that of dust particles
Consider the following statements: 1. The Earth's magnetic field has reversed every few hundred thousand years. 2. When the Earth was created more than 4000 million years ago, there was 54% oxygen and no carbon dioxide. 3. When living organisms originated, they modified the early atmosphere of the Earth. Which of the statements given above is/are correct?
Consider the following statements about the Atmospheric pressure phenomenon and identify the correct ones. Atmospheric pressure is basically a force in any area pushed by any surface by the weight of the Earth's atmosphere.  The atmospheric pressure increases with an increase in the altitude for any region.  The earth's rotation affects the pressure of the atmosphere in various ways.
Statement I: The gases are separated in Earth’s atmosphere. Statement II: Separation of gases in the Earth’s atmosphere occurs because of gravity.
Which of the following statement is are correct? (1) Water vapor in the atmosphere increases with altitude. (2) Ozone Layer is found in stratosphere where airplanes fly. (3) Rotation of earth, its angle of inclination, and transparency of the atmosphere are associated with insulation of the surface of the earth. (4) Exosphere is the atmospheric layer which reflects radio waves
Consider the following statements (A), (B) and (C) and choose the correct option. A. The gravitational force of earth holds the atmosphere around it B. Atmosphere only consists of few gases. C. Biosphere is a narrow zone of the earth where only land and air interact with each other.