Answer:
The correct answer is option a. "Transcription would not occur at high levels in either the presence or absence of arabinose".
Explanation:
The ara operon, also known as the L-arabinose operon, is a series of related genes that are transcribed within the same transcript and are all related to the metabolism of L-arabinose. Among the proteins translated from the ara operon, the AraC protein that binds to RNA Polymerase is the one that recognizes L-arabinose and enhances ara operon transcription in its presence. Therefore, if a mutation removes the gene that encodes for the AraC protein, transcription would not occur at high levels in either the presence or absence of arabinose.
The answer is true. When two tectonic plates are sliding past each other, it results in shear stress, and shear stress leads to an earthquake.
Answer:
directional selection, stabilizing selection
Explanation:
Directional selection is a type of natural selection that favors one extreme phenotype over other phenotypes, thereby modifying allele frequency in the direction of the favored phenotype. This type of positive selection is the main cause of phenotypic diversification. In the USA, the environment created a selection pressure that favored individuals that don't have the defective sickle-cell allele, thereby reducing its frequency in this population. Stabilizing selection, also known as balancing selection, is a type of natural selection where the most common phenotype is selected in the population, thus predominating in future generations. In equatorial Africa, the defective sickle-cell allele is present in a high frequency because individuals that are heterozygous for this allele are less susceptible to malaria, and therefore balancing selection should maintain this allele in the African population.
(There are thousands of odorant molecules, and our olfactory system can detect and identify each. Whenever we smell something, olfactory receptors traveled and received by our olfactory bulb. After the message was received the odor perception will determine and identify the description of the smell. )
Translated by Google...
<span>Istnieją tysiące cząsteczek zapachowych, a nasz układ węchowy może je wykryć i zidentyfikować. Kiedy tylko coś czujemy, receptory węchowe podróżowały i odbierane przez naszą węchową żarówkę. Po otrzymaniu wiadomości odbiór zapachów określi i zidentyfikuje opis zapachu.</span>