Explanation:
The problem says that the hairless phenotype never breeds true. That means that it's not the result of a homozygous genotype (H₁H₁ or H₂H₂), so it is caused by the heterozygous genotype (H₁H₂).
The <u>expected </u>offspring from the cross between two Mexican hairless would be:
<h3>P
H₁H₂ x
H₁H₂</h3><h3>F1 1/4
H₁H₁, 2/4
H₁H₂ and 1/4
H₂H₂.</h3>
And the <u>expected</u> phenotypic ratio 3:1. However, the observed offspring shows a 2:1 ratio. What's happening?
If the observed phenotypic ratio in the offspring of a monohybrid cross (a single gene with two alleles) is 2:1, we can suspect that one of the genotypes is lethal in homozygosis and therefore does not appear in the progeny (the puppies are born dead).
If we proposed that the H₂ allele is lethal in homozygosis, then:
- The H₁H₁ genotype would cause normal puppies --> 1
- The H₁H₂ genotype would cause hairless puppies --> 2
- The H₂H₂ is lethal and causes the death of puppies --> 0
The phenotypic ratios change to 2:1, as observed in the experiment.
Answer:
The correct answer is A. The cartilaginous structure between the "throat" and the trachea is the larynx.
Explanation:
The larynx is a tubular organ. The larynx wall is composed of 9 pieces of cartilage. Three are odd (thyroid cartilage, epiglottis and cricoid cartilage), and three pairs (arytenoid, cuneiform and corniculate cartilage). In addition, it communicates the pharynx with the trachea and is in front of it.
Answer:
8 chromosomes in its skincell
Explanation:
Sex organ is (n)
Other than sex organ is 2(n)
Answer:
The correct answer is option A. "the temporary hyperpolarization of the axon membrane following the action potential spike".
Explanation:
Action potentials, also known as "spikes" or "impulses", are electric impulses that neurons use to send information from the cell's body down to the axon. The impulses are created when ions travel across the neuron's membrane creating a depolarization current. This depolarization current is responsible for an temporary hyperpolarization of the axon membrane following the action potential spike. When neurons are hyperpolarized they are not able to produce another action potential. In consequence, actions potentials move in one direction along the neuron away from the cell body, as well as, adjacent locations go trough similar depolarization processes.