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Inessa05 [86]
3 years ago
7

Natural selection results and change over time by acting on trates that are???

Biology
2 answers:
Y_Kistochka [10]3 years ago
4 0
Natural selection results and change over time by acting on traits that are new
Sophie [7]3 years ago
3 0
B. Heritable.

Disregard other answer, that is horribly wrong.
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Pedigrees are used to help geneticists understand how traits are inherited between generations. The Romanovs, a Russian royal fa
inysia [295]

Answer:

Waldemar carried the recessive allele.

Explanation:

The carrier is the individual that has the affected allele or mutation but does not express the trait, or might express it in different levels. Although, as the person carries the mutation, she or he might transmit the genetic mutation associated with a disease to the progeny.  In general, these diseases are inherited as recessive traits.

So, in the exposed example we know that:

  • hemophilia is a sex-linked disorder
  • hemophilia is determined by a recessive allele on the X chromosome.
  • Irene is a carrier.
  • Her husband is not a carrier.
  • Her children Waldemar and Henry have hemophilia.

If Irene is a carrier, this means that she is heterozygous and that her genotype is X⁺X⁻ (Being the symbol + the dominant allele, and - the recessive one for that expresses the trait)

The fact that Irene´s husband is not a carrier means that his genotype is X⁺Y

Their boys Waldemar and Henry have hemophilia, so both their genotypes are X⁻Y

The best evidence to prove that Irene was heterozygous for hemophilia is that Alice carried the recessive allele.

  • Alice is Irene´s Mother, and she is a carrier as well. Irene´s father, Louis, is not a carrier, so she could have inherited a dominant allele from her father and a recessive allele from her mother, X⁺X⁻, or she could have inherited two dominant alleles from both her parents X⁺X⁺. This is not proof enough of Irene being heterozygous.
  • The fact that Alexandra, Irene´s sister, was also a carrier does not say anything about Irene´s genotype, because they could both share the same genotype or not. This is not proof of Irene being heterozygous.
  • Frederick (her brother) was hemophilic.  He received a recessive allele from Alice, but this does not say anything about Irene´s genotype.  
  • The fact that Waldemar (her son) was hemophilic, is the best evidence to prove that Irene was heterozygous for hemophilia. Walderman received the Y chromosome from his father and an X chromosome from his mother. The X chromosome that he received from his mother carried the recessive allele for the trait, and this is why he had hemophilia. This means that there is no best evidence for Irene´s genotype than her son´s genotype.

 

6 0
4 years ago
Write a paragraph explaining how eukaryotic cells arose from prokaryotic cells.
timurjin [86]
Cells are divided into two main classes, initially defined by whether they contain a nucleus. Prokaryotic cells (bacteria) lack a nuclear envelope; eukaryotic cells have a nucleus in which the genetic material is separated from the cytoplasm. Prokaryotic cells are generally smaller and simpler than eukaryotic cells; in addition to the absence of a nucleus, their genomes are less complex and they do not contain cytoplasmic organelles or a cytoskeleton (Table 1.1). In spite of these differences, the same basic molecular mechanisms govern the lives of both prokaryotes and eukaryotes, indicating that all present-day cells are descended from a single primordial ancestor.

Need more? Reply with help or hit the thanks. If you think this can help others just brainlist. :)
7 0
3 years ago
"Which statement concerning the oxygen level in the lake can be inferred from the graphs?
KatRina [158]
After seeing a graph represented below, I have recognized the correct answer, and I think that the statement concerning the oxygen level in the lake which can be inferred from the graphs is being revealed by the option 1 -<span>Trout and whitefish require higher oxygen levels than do carp. As you can see the oxygen line on the graph shows that carp does not require as much oxygen as whitefish does require, as level is increasing on the left side.
Hope you will find it helpful!
Regards.</span>
8 0
4 years ago
What would happen if the arteries couldn’t deliver oxygen to your cells?
Anni [7]
Then the imposters will win
6 0
3 years ago
Read 2 more answers
- How would you classify the relationship between coral and the small crabs?
skelet666 [1.2K]

Answer:

Explanation:

How would you classify the relationship between coral and the small crabs? Their relationship is mutualistic, as the crabs provide protection for the coral reef and the reef provides the crabs a home.

7 0
2 years ago
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