Answer:
d. 28,650 years
Explanation:
Since 14C has a single half-life of 5,730 years
The number of years that is going to make up 5 half-lives for 14C will be;
5,730 years × 5 = 28,650 years
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.
Heart rate decreased suddenly and then MAP immediately fell because peripheral blood vessels were extensively vasodilated.
Explanation:
A VO2 max test is a clinical test done in a lab and is the ‘golden standard’ for measuring the potential and cardio-respiratory endurance of athletes and bikers.
It measures the oxygen carrying capability through a graded step test which determines the average power output. The maximal oxygen uptake along with cardiorespiratory responses is measured.
As per exercise physiology, the heart rate and cardiac output increases with exercise. When the potential is less, the resistance decreases, heart rate and mean arterial pressure also decrease
.
Answer:
They release chemical messengers to communicate with cells they may or may not be in direct contact with.
Explanation:
Unicellular organisms such as bacteria or yeast, 'talk' to each other through the release of chemicals. In bacteria, this is known as quorum sensing which allows them to determine the surrounding bacterial population density. In yeast, one of the more popular pathways is known as the mating factor pathway, which allow the organisms to find mates. Whereas, in multicellular organisms (such as humans), this chemical release allows for cell-cell co-ordination which keeps the system functioning correctly.
