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QveST [7]
3 years ago
10

How is modern earth different from earth over 4 billion years ago?

Biology
1 answer:
igor_vitrenko [27]3 years ago
5 0

Earth and its atmosphere are continuously altered. Plate tectonics shift the continents, raise mountains and move the ocean floor while processes not fully understood alter the climate. Such constant change has characterized Earth since its beginning some 4 billion years ago.

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Why are organelles surrounded by membranes?
ehidna [41]
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7 0
2 years ago
Please help
Ludmilka [50]
A memory B cell is kinda of how it sounds it has a memory of what your body has fought before such as a virus and can stimulate a response quicker then the first time you encountered it. 

If you lack memory B cells your body doesn't built up the same immune response when you come into contact with the virus again.

"Vaccination would prevent further disease" Incorrect, a vaccine lets you build up memory cells to combat the disease if you lack them you cannot build up a defense.
"Vaccination would not prevent further disease" Correct, a vaccine can be a dead version of a virus or parts of a virus that shows your body what to respond to quickly in the future. If you body cannot make memory b cells it wouldn't help to use a vaccine. Your body wouldn't keep a memory of it being bad.
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6 0
3 years ago
The syntenic genes A and Z are linked. A cross between two parents, AAZZ and aazz, produces F1 progeny with the AaZz genotype. W
garik1379 [7]

Answer:

The possible arrangements of alleles on the F1 progeny's chromosomes will be AZ/Az or aZ/az

Explanation:

The genotype of F1 progeny  is AaZz

The allele pair of gametes would contain one allele for characteristic represented by "A or a" and other allele for characteristic represented by Z or z"

Thus, total four allele pairs will be formed.

First allele pair would be - AZ

Second allele pair would be - Az

Third allele pair would be - aZ

Fourth allele pair would be - az

Hence, the possible arrangements of alleles on the F1 progeny's chromosomes will be AZ/Az or aZ/az

8 0
3 years ago
Why is abortion important?
Ksenya-84 [330]
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5 0
1 year ago
When we say that a galaxy is 5000 light years from earth we are actually describing
Stella [2.4K]
<span>A light year refers to a very big amount of distance and is a measurement termed as an astronomical unit of measure. When you say that a galaxy is 5,000 light years away we are actually describing the speed of light within a year. One light year is actually equivalent to 9, 500, 000, 000, 000 kilometers. Just imagine how big or how far that galaxy is when you multiply those kilometers by 5,000?</span>
5 0
3 years ago
Read 2 more answers
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