Answer:
{Dear:friends name}
I'm writing this letter to tell you congrats on getting admitted into your dreams school!!
I know how nervous you were when the letter came.
i'm going to miss seing you around but i know that you are going to have so much fun when school starts up again .
<u>Answer:</u>
Cyanobacteria start producing pure oxygen around 200 million years ago.
<u>Explanation:</u>
Many scientists believed that Earth did not have any oxygen. Cyanobacteria or the blue green algae are the microbes which produced oxygen for the first time with the help of photosynthesis. This was around 4.5 billion years ago: after Hadean eon.
They were very simple, but they produced oxygen in the early earth’s atmosphere. So, they brought evolution on earth. This “blue-green algae” exists in salt water, rocks and soils and play a major role in maintaining the ecosystem.
Answer:
50%
Explanation:
Let the allele for red-green color blindness be represented by c.
Normal vision woman whose father is color-blind will be 
Color-blind male will be 
x
Progeny: 
(See the attached image)
<em>Out of the 2 male progeny, 1 is affected for color-blindness while the other is not affected. This gives a 50% probability that a son of the couple will be color-blind.</em>
But this rule rule is applicable only for double stranded DNA molecule. The possibility of Adenine=40% and Thymine=60% is only in single stranded DNA molecule. In the question, the DNA sample referred is a single stranded DNA. hope it helps :D
