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2 years ago

The placenta develops from the outer cells of the

1 answer:

4 0

<span>blastocyst The outer layers of the blastocyst turn in to the trophoblast after implantation. The trophoblast forms the placenta.</span>

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Living organisms must acquire energy from their environment. Examples of adaptations that help organisms acquire this energy inc

krek1111 [17]

Answer:

The correct answers are Option A and B

Explanation:

A. The dark, heat-absorbing coloration of a reptile.

B. The fangs and claws of a lion

3 0

2 years ago

5. The F2 generation of a cross between a parental tall and a parental short pea plant is 298 tall plants and 102 short plants.

Vadim26 [7]

Answer:

The answer is XX.

Explanation:

Let us say that X is the dominant gene and x is the recessive gene for the height of the pea plants. Pea plants need to be homozygous or heterozygous to have the short phenotype which means it needs to have the genotype xx or Xx.

The F2 offspring has a ratio of 74,5% tall plants and 25,5% short plants. For these results, the stem height pea plant needs to be homozygous which is an XX genotype for the tall pea plant.

I hope this answer helps.

7 0

2 years ago

the development of which type of microscope made it possible to create high-resolution three-dimensional images of living cells

enot [183]

Cryo-electron microscopy (cryo-EM), or electron cryomicroscopy, is a form of transmission electron microscopy (TEM) where the sample is studied at cryogenic temperatures (generally liquid-nitrogen temperatures). Cryo<span>-EM is gaining popularity in structural biology.

I hope my answer has come to your help. God bless and have a nice day ahead!
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7 0

2 years ago

Read 2 more answers

In fruit flies, straight wings are dominant and curly wings are recessive. What will the generations look like? Assume that Mend

anzhelika [568]

Answer:

The P generation has straight wings and curly wings.

The F1 generation has all straight wings.

The F2 generation has straight wings and curly wings.

Explanation:

This question involves a single gene coding for wing shape in fruit flies. The allele for straight wings (S) is dominant over the allele for curly wings (s). This means that allele "S" will mask the phenotypic expression of allele "s" in a heterozygous state.

According to the question, the cross follows all Mendel's method of crossing two true breeding parents with opposite traits. Hence, the parent generation (P generation) will be between a truebreeding straight wings parent (SS) and a truebreeding curly wings parent (ss). (See attached image for full cross).

Since the straight wing allele (S) is dominant, all the F1 offsprings will possess straight wings with the genotype: Ss, which is heterozygous.

If this F1 offsprings are self-crossed i.e. Ss × Ss, four possible offsprings in the phenotypic ratio 3 straight wings : 1 curly wing will be produced in the F2 generation. The offsprings will possess the following genotypes: SS, Ss, Ss, and ss.

Offsprings SS, Ss, and Ss will all be phenotypically straight-winged

Offsprings ss will be phenotypically curly-winged.

In overall, this means that P generation has both straight and curly wings (SS and ss), F1 generation has only straight wings (Ss), F2 generation has both straight and curly wings (SS, Ss and ss).

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2 years ago

The phrase darwin used to describe his broad theory of evolution is ''descent with .'' 2. all of life is related through common

mario62 [17]

1. The phrase Darwin used to describe his broad theory of evolution is ''descent with modification.

2. All of life is related through common ancestry, accounting for the Unity.

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2 years ago