Complete question:
Suppose "A" is a dominant gene for the ability to taste phenylthiocarbamide and "a" is a recessive gene for the inability to taste it. Which couples could possibly have both a child who tastes it and a child who does not?
a. father AA, mother aa
b. father Aa, mother AA
c. father Aa, mother Aa
d. father AA, mother AA
Answer:
c. father Aa, mother Aa
Explanation:
According to the given information, the ability to taste phenylthiocarbamide is a dominant trait and is imparted by the allele "A". This phenotype would be expressed in both homozygous and heterozygous conditions. The non-taster phenotype would be expressed in the homozygous recessive genotypes only.
To have both taster and non-taster children, both the parents should have at least one copy of the recessive allele. Among the given options, the father with genotype Aa and the mother with genotype Aa have the possibility to have both taster and non-taster children.
Aa x Aa= 3/4 taster (1/4 AA and 1/2 Aa): 1/4 non-taster (1/4 aa)
Answer:
A dorsal root (sensory or afferent) and a ventral root (motor or efferent) originate from the medulla. They unite near the intervertebral foramen, forming the spinal nerve. The nerves emerge from the intervertebral foramen, dividing into ventral and dorsal ramus.
Explanation:
The nerve is a set of nerve fibers perceptible to the naked eye and wrapped in connective tissue. They are made up of roots, trunks and nerve branches (some of them come together and form plexuses).The spinal nerve originate from the spinal cord in the form of 31 pairs: 8 cervical, 12 thoracic, 5 lumbar, 5 sacral and 1 coccygeal. They emerge from the spinal cord through two roots: dorsal roots, made up of sensory fibers that come from the sensory neurons of the spinal ganglion and that penetrate the spinal cord through the posterolateral and ventral root, made up of motor fibers, coming from the motor neurons of the anterior horn and visceral of the lateral horn of the gray matter of the spinal cord. This root exits the spinal cord through the anterolateral groove, then joins the posterior root to form the spinal nerve, which exits the vertebral canal through the corresponding intervertebral foramen.Each spinal nerve, after leaving the vertebral canal, emits two primary ramus: the dorsal ramus, contains somatic and visceral fibers that go to the skin and muscles of the back and the ventral ramus, which supplies the ventrolateral surface of the skin, body wall and extremities.
This because ice is less dense than water of particular temperature range. Water reaches its maximum density at 4 degrees. Ice is important especially for aquatic life in the polar regions. Polar bears give birth and hunt on sea ice and they need it to travel from one region to another. The ice edge in coastal areas is an important feeding ground for the walrus that uses the ice as diving platforms to feed on clams on the sea floor. Ice algae grow at the porous bottom of sea ice and form the base of the unique marine food web connected to sea ice
True....................................................................
