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Dafna11 [192]
3 years ago
6

Although earth is estimated to be 4.5 billion years old, and although life first appeared about 4 billion years ago, plants did

not appear until about _______ years ago.
Biology
1 answer:
timurjin [86]3 years ago
3 0
470 million years ago
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In piranha, fish with large teeth represent the dominant trait. Because the dominant trait masks the recessive trait, in a popul
vodomira [7]

Answer:

B. 25%

Explanation:

Assuming the trait for teeth size is represented by the allele A. large teeth size is dominant and will be represented by A while small teeth size will be represented by a.

Assuming that the population of 1,000 [piranhas are all heterozygotes and they crossbreed with one another:

Aa   x   Aa = AA, Aa, Aa and aa

The ration of piranhas with large teeth to that of the small teeth is 3:1 or 75:25.

Hence, about 25% of the next generation of the population is ecpected to have small teeth.

The correct option is B.

8 0
3 years ago
The ​ DNA molecule is very similar among all living things. The pairings are always the same and there are only six components t
Gala2k [10]

Answer:

The reason why there is so much diversity of life, despite the fact that DNA is the same for all living things, the pairings are always the same and there are only six components that make up the DNA, is that sequences of base pairs are different.

Explanation:

DNA is the molecule that contains all the genetic information, whose structure consists of four nitrogenous bases, adenine, guanine, thymine and cytosine, plus deoxyribose and a phosphate group. This DNA molecule constitutes the basis of life and inheritance of all living beings.

The nitrogenous bases of DNA are found in a number and specific sequences, which determine the proteins and biomolecules that must be synthesized in the cells.

What makes different types of living beings and diversity of life is the length of the DNA and the sequence of bases that form part of each molecule.

The other options are not correct because:

  • <em>The sugar component of DNA is always the same, not different. </em>
  • <em>Organisms always use DNA in the same way. </em>
  • <em>The DNA molecule is always the same.</em>
3 0
3 years ago
Anytime you speculate about a problem and think of an answer based on what you
Natalija [7]

Answer:

b. False

Explanation:

A scientific theory must have strong support from testable facts that are confirmed (or rejected) by observational and/or experimental procedures. The scientific method is a rigorous process that consists of arising a conjecture (hypothesis) which can be subsequently used to make predictions from its logical consequences, and finally to obtain information from empirical observations/experiments in order to obtain a conclusion about the veracity of the scientific claims (i.e., a hypothesis must be testable). In consequence, a scientific theory can not be based only on 'light' conjectures, but trustworthy observational data from the real world.

3 0
3 years ago
Please help me with this it’s so hard
Deffense [45]

Answer:

1: Frond's

2:Pistil

3:Gametes and spore's

4: photosynthesis

5: Spore

6:Stigma or ovule

7:Ovary

Hope this helps!

5 0
2 years ago
About fifty thousand years ago ______ formed meteor crater
bixtya [17]
D. an asteroid because an asteroid is the only thing that can form a meteor crater. 
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3 years ago
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