Answer:
A. I, II, III, and V only
Explanation:
In genetics, an allele refers to the specific form of a gene, which encodes traits. These alleles are usually in pairs in a diploid organism i.e. an organism with two sets of chromosomes. According to Gregor Mendel,
- An allele can either be DOMINANT when the allele masks the phenotypic expression of its allelic pair while the allele that is masked is said to be RECESSIVE.
- Two alleles can also be CO-DOMINANT when the two alleles are neither dominant or recessive over one another but are simultaneously expressed in that particular gene.
- Alleles can also be INCOMPLETELY DOMINANT when one allele is not completely dominant over the other, hence, forms a third intermediate phenotype when in combination with the second allele i.e. in an heterozygous state.
Based on this, an allele can be dominant (I), recessive (II), codominant (III), and incompletely dominant (V).
Answer:
True
Explanation:
Some deviations from normal homeostasis activate the positive feedback loops to control the conditions which are otherwise regulated by negative feedback mechanisms.
For example, the blood levels of respiratory gases and H+ ions are regulated by a negative feedback system via chemoreceptors. The increased partial pressure of carbon dioxide gas and lowered pH or lowered partial pressure of oxygen in the blood are sense by central and peripheral chemoreceptors which in turn activate the neurons of the dorsal respiratory group (DRG).
The activated DRG triggers an increased in the rate and depth of the breathing to facilitate the inhalation of more oxygen and exhalation of CO2 to restore the normal levels.
However, hypocapnia inactivates the chemoreceptors and does not allow negative feedback to restore the normal CO2 levels in the blood.
Under such conditions, the positive feedback loop stimulates the DRG neurons more strongly in response to the increased partial pressure of CO2 above the normal levels than when the partial pressure of oxygen falls below the normal level. These dangerously lowered oxygen levels may also cause fainting.
Answer:
This is the spring tide: the highest (and lowest) tide. Spring tides are not named for the season. This is spring in the sense of jump, burst forth, rise. So spring tides bring the most extreme high and low tides every month, and they always happen – every month – around full and new moon.
Explanation:
Choose and pick may be an example
