Here something that might help
<span>
Most scientists believe that for half of </span>Earth's<span> 4.6-billion-year history, the</span>atmosphere<span> contained almost no </span>oxygen<span>. Cyanobacteria or blue-green algae became the first microbes to produce </span>oxygen<span> by photosynthesis, perhaps as long ago as 3.5 billion years ago and certainly by 2.7 billion years ago.</span>
Answer:
<em>energy star.</em>
Explanation:
Its main objective is to help consumers, businesses, and industry save money and protect the environment through the adoption of energy-efficient products and practices.
Hello there.
<span>Regulation of the cell cycle is dependent upon cyclins and cyclin-dependent kinases. The key(s) that allows a cell to progress beyond the restriction point is (are)
</span><span>c. cyclin A and Cdk2.
</span>
The causitive agent of the cohesion-tension model of xylem transport is transpiration. During the process of transpiration, water vapor is lost from the stomata of the leaf. To replace this water, water from adjacent cells is withdrawn. The water molecules stick together due to cohesion and are transported upwards through the stem in the form of a stream.<span />
<span>Pigeons learn to flap their wings to avoid shock more easily than they learn to peck a disk to avoid shock. they learn to flap their wings to obtain food less easily than they learn to peck a disk to obtain food.
That's what'd I'd assume the answer would be.</span>
