Fish has a singular circulatory system, means the blood carrying oxygen from pulmonary circuit will be dumped into the same chamber as the blood carrying wastes and CO2 in the heart, because the heart has only one chamber.
amphibians has a 3 chamber heart, but still not a complete separated pulmonary circulation. However, it does have 2 loops at this stage. Of course birds and mammal also has this feature. So the distinction will be between fish and amphibian, which is the evolutionary double loop pathway.
Answer:
D) Each egg has a one-fourth chance of having either blue long, blue short, orange long, or orange short
Explanation:
The female individual looked at in this question involves two distinct genes coding for color and length. According to the question, the female contains in her genome, orange and blue alleles on one locus and long and short alleles on another locus (i.e. OoLl, where gene O is for color and gene L is for lenght).
The female will undergo meiosis, in which the alleles of each gene will separate into gametes independently of one another (according to Mendel's law of independent assortment) i.e. each gamete will equally likely contain one maternal and paternal allele of each gene.
Due to a unique phenomenon called CROSSING-OVER, which occurs in the prophase stage of meiosis I, four genetically different gametes can be produced. The alleles will be combined in the gametes (eggs) in a way that each egg is likely to contain 1/4 probability of having a blue long (oL), orange long (OL), orange short (Ol), and blue short (ol). This combination is only possible if the alleles of each gene assort independently.
Answer:
In the north, caribou are an iconic circumpolar species whose distribution ranges from the arctic and tundra to the boreal and mountains of Europe, Siberia and North America. Caribou are members of the cervidae family, a branch of ungulates, who grow antlers every year. The process of shedding and re-growing antlers year after year is a unique process. In just a matter of weeks, bull caribou can grow antlers which weigh up to 20 pounds and are over a meter in length!
Explanation:
Out of the following given choices;
<span>A. </span>The sodium channels would open and close randomly, regardless of the presence of light.
<span>B. </span>The sodium channels would remain closed in the light and the dark, even when cGMP decreases after light stimulation.
<span>C. </span>The sodium channels would remain open in the dark and close rapidly to the light.
<span>D. </span>The sodium channels would remain open longer, even when cGMP decreases after light stimulation.
The answer is D. cGMP maintain the sodium channels open when there is no light stimulation. This ensures that there is high intracellular Ca2+ concentration due to the Na+/Ca2+-K+ exchanger. When cGMP is hydrolyzed in light stimulation cascade, the channels close causing hyperpolarization of the rod cells.