Answer:
2. Fresh water is essential to all life on earth.
and
4. Most of earth's water is stored in the oceans
Explanation:
Hope this helps you! :)
Answer:
Hemoglobin transfers oxygen from the lung to the muscles, brain, and other organs, and also helps the body to convert carbohydrates and fat into energy.
Answer:
sunlight
Explanation:
at the angle the earth is at, sunlight hits the equator almost directly, as well as the equator being closer to the sun.
Answer:
Watson and Crick proposed the double helical model of DNA.
Explanation:
- This model says that DNA exist as double helix. It has two polynucelotide strands running in opposite direction i.e the strands are anti-parallel.
- Each polynucleotide strand is made up of several nucleotide liknked together by phophodiester bonds.
- The two strands are not coiled upon each other but the double strand is coiled upon itself around a common axis like the spiral stair case. Here base pairs forms the stairs and backbone of two strands form railing. Back bone contains sugar and phosphate.
- The base pairing is specific, adenine always pairs with thymine and guanine always pairs with cytosine. Thus if we see any base pair, it consists of one purine and one pyrimidine.
- The two strands of DNA thus show complementary base pairing.
- The strands are held together because of hydrogen bonding between the bases in opposite strand.
- One full helical turn involves ten base pairs and the base pairs are stacked 3.4 A apart.
- This form is called as B-form of DNA.
I believe the first answer is #4 and the second is #1. Please correct me if I am wrong.
