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Citrus2011 [14]

2 years ago

11

All BUT one factor contributes to natural selection. That factor is A) mutation. B) random mating. C) genetic drift. D) environm

ental factors.

2 answers:

Gekata [30.6K]2 years ago

8 0

The answer is b or d but I really think its b

Vanyuwa [196]2 years ago

3 0

B. Mutation i think
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An additional gene, gene W, was also examined. A test cross was made between true-breeding EEWW flies and EEWW flies. The result

Debora [2.8K]

This question is incorrect but here is the correct question below;

An additional gene,gene W was also examined. a test cross was made between true breeding EEWW flies and eeww flies. The resulting F₁ generation was then crossed with eeww flies. 100 offspring in the F₂ generation were examined and it was discovered that the E and W genes were not linked.

Which is the correct genotype of the F₂ offspring if the genes were linked and if the genes were not linked?

a) Linked: 50% EeWw and 50% eeww; not linked: 25% EeWw, 25% Eeww, 25% eeWw and 25% eeww.

b) Linked: 25% Eeww, 50% eeWw; not linked:parental genotypes EeWw and eeww.

c) Linked genotypes (EeWw and eeww) and recombinant genotype ( Eeww & eeWw) in the F₂ generation are nearly the same irrespective of their linkage.

d) Linked: mostly with parental genotypes, Eeww and eeWw; unlinked: 25% EeWw and eeww with 75% Eeww and eeWw.

Answer:

a) Linked: 50% EeWw and 50% eeww; not linked: 25% EeWw, 25% Eeww, 25% eeWw and 25% eeww.

Explanation:

a test cross was made between true breeding EEWW flies and eeww flies

If EEWW self crossed, we have the following ( EW, EW, EW, EW)

Also, for eeww, we have ( ew, ew, ew, ew)

EW EW EW EW

ew EWew EWew EWew EWew

ew EWew EWew EWew EWew

ew EWew EWew EWew EWew

ew EWew EWew EWew EWew

All offspring are (EWew)

The question goes further by saying "The resulting F₁ generation was then crossed with eeww flies".

And we are asked to find the correct genotype of the F₂ offspring if the genes were linked and if the genes were not linked

∴

To determine the offsprings of the linked genes we need to go by the definition and understand what linked genes are: Linked genes are genes that are physically close together on the same chromosomes. Effect of recombinantion on linked genes, results in gene swaps which occur in chromosomes that are homologous.

Having said that; If EWew × eeww

we have; EW & ew × ew & ew

EW ew

ew EeWw eeww

ew EeWw eeww

offspring that

are linked in ⇒ EeWw EeWw & eeww eeww

F₂ will be

$\frac{1}{2}$ = 50% of EeWw of the total 100 offspring in the F₂ cross

$\frac{1}{2}$ = 50% of eeww of the total 100 offspring in the F₂ cross

∴ Linked genes = 50% EeWw and 50% eeww.

For unlinked genes; If EWew × eeww

if rearrangement occurs in EWew and EWew self crossed, we have ( EW,Ew,eW,ew) as the traits needed for the unlinked gene F₂ crossing.

Also ewew will be (ew, ew, ew, ew).

EW Ew eW ew

ew EeWw Eeww eeWw eeww

ew EeWw Eeww eeWw eeww

ew EeWw Eeww eeWw eeww

ew EeWw Eeww eeWw eeww

We have the following results for the unlinked genes

$\frac{1}{4}$ = EeWw 25% of the total 100 offspring in the F₂ cross

$\frac{1}{4}$ = Eeww 25% of the total 100 offspring in the F₂ cross

$\frac{1}{4}$ = eeWw 25% of the total 100 offspring in the F₂ cross

$\frac{1}{4}$ = eeww 25% of the total 100 offspring in the F₂ cross

∴ not linked: 25% EeWw, 25% Eeww, 25% eeWw and 25% eeww.

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The esophagus is located in the ___________.

kaheart [24]

You esophagus is your throat.

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3 years ago

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A seed that is dispersed to an area far away from the parent plant will always face less

Stolb23 [73]

D
Less <span>competition with the parent plants. by being dispersed further, they will face competition but not with their parent plants.</span>

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To take in matter or energy<br> collection<br> liver<br> composition<br> absorption<br> Ok

kolbaska11 [484]

Answer: absorption
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In this case, matter and energy is absorbed.

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2 years ago

Disturbances to an ecosystem, such as fires and floods, are often seen as negative. Describe a situation where

trasher [3.6K]

Answer:

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A branch of science, which deals with the natural procedures that comprise fire within an ecosystem and the ecological influences it imparts, the association between the biotic and the abiotic constituents of an ecosystem with the fire, and the role played by fire within an ecosystem is termed as a fire ecology.

Different kinds of ecosystems like savanna, prairie, coniferous forests and chaparral have originated by the contribution of the fire, which plays an essential role in the renewal and vitality of the habitat. Different kind of plant species needs the assistance of fire to establish, to reproduce, or to germinate. In case, if the suppression of wildfire takes place, it will eventually result in the eradication of various plant species and the animals that rely upon them.

4 0

3 years ago