The DNA molecule is composed of two strands with the help of hydrogen bonds which is doubl helix <span> At each end of the double helix, one strand is 5' and the other is 3'.the two strands are anti parallel so the correct option is
</span> They are oriented in opposite directions
it is a test where you can look in books, the internet, and several other places to find the answers.
C.Dark-colored soil.It indicates a high percentage of organic matter in the soil.The darker the soil,the higher its percentage of organic matter.Dark soil are very fertile and and suitable for any crop cultivation.
Explanation:
The evolution of photosynthetic organisms, about 4.9 bilion ago, changed the earth’s atmospheric composition. The photosynthetic organism took up most of the carbon dioxide and evolved oxygen. They are responsible for the Great Oxygenation Event.
As oxygen filled the atmosphere, it became possible for ozone (O₃) to form. In the upper atmosphere ultraviolet light rays split molecular oxygen into atomic oxygen ( through photolysis), and the oxygen atoms react with oxygen molecules (O₂) to form ozone (O₃). This is a forward and reverse reaction because the ozone also decomposed back to molecular oxygen.
The formation of ozone helped the colonization of land by life because ozone prevents most UV from reaching earth's surface and protected the genetic material from the ionizing effect of ultraviolet rays.
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For more on ozone check out;
brainly.com/question/11525527
brainly.com/question/13571817
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A) The stars core shrinks
The star will contract under the weight of gravity.
When it contracts it will heat up and expand to a red giant.
When the star runs out completly of helium it would emit gasses and form a star nebula.
It would then become a white dwarf then into a black dwarf.