What created oxygen in the early atmosphere

Photosynthetic bacteria

Asteroids hitting the earth

plankton

Volcanic eruptions

forests

How can i use mitochondria in a sentence

Explain why arteries are better suited for blood leaving the heart and explain why veins are better suited for blood returning to the heart.

Which of the following statements is true? Good physical health requires at least 30 minutes of aerobic exercise each day. Snuff does not contain actual tobacco, but it is considered a form of tobacco use.

If a DNA molecule is compared to a spiral staircase what parts make up the steps

As your group adds to the graphic, your teacher tells you to add an example for each of the four boxes at the base.

What is ozone? 1. dissolved oxygen 2. the main catalyst in photosynthesis 3. a type of oxygen 4. a form of calcium carbonate

What are two advantages of burning garbage for fuel?

The measurement of the distance from the crown of the infant's head to the infant's heel, while the infant is lying on his/her back with legs extended, is a measurement of:

How many pairs of autosomes does this karyotype have?

If a theory is challenged by new evidence, which of the following couod occur? A. the theory could be altered B. the theory is accepted, not the evidence C. the evidence is wrong D. a vote is taken to accept new evidence