Hot , dry weather is the answer
Answer:
smooth was dominant over that for wrinkled
Explanation:
In complete dominance, a gene may have two different variants or 'alleles', dominant and recessive. A dominant allele is a gene variant that is able to produce a certain phenotype, even in the presence of other alleles, while a recessive allele is a gene variant that is masked by the dominant allele in heterozygous individuals (i.e., individuals that inherited different alleles from each parent). By crossing smooth and wrinkled pea plants, Mendel observed the offspring (F1) were smooth rather than mixed, indicating one type of seed texture was dominant over the other. Subsequently, Mendel observed that alleles for different traits (e.g., seed texture and seed color) assorted independently during meiosis.
That's what is called competitive enzymatic regulation. If there are more of that substance than the enzyme substrate, then most of the enzyme, if not all depending on the substance's concentration, will be inhibited on its action. If there are more substrate then the competitive substance, the expected reaction for that enzyme will happen at an expected rate. If the ratio substrate:substance is 1:1 then the reaction enzyme-substrate is very slowed down.
I believe that the answer to your question would be A. Heart Begins.
The crayfish have its nerve cord on the ventral side rather than on the dorsal side. The ventral side is under the Crayfishes' exoskeleton, as opposed to the dorsal side where the exoskeleton is . If it is attacked it will be from the dorsal side and the nerve cord would be snapped easier. The function of the nerve cord is that if it gets attacked by a predator they will go for the top and it will still be able to move.