Answer: False
Explanation:
Acetylcholine functions in the central nervous system and peripheral nervous system both as activator and inhibitor.
It can cause the skeletal muscle to contract and it also inhibits the activation of the cholinergic system.
Whereas, the norepinehrine functions to mobilize the brain and body for actions. It is released lowest at the the time of sleeping , it shoots up at the time we are awaken and is highest at the time of stress.
<h3>Natural selection:-</h3>
Natural selection is the process through which populations of living organisms adapt and change. Individuals in a population are naturally variable, meaning that they are all different in some ways.This variation means that some individuals have traits better suited to the environment than others.
<h3>Evolution occur in natural selection:-</h3>
Through this process of natural selection, favorable traits are transmitted through generations. Natural selection can lead to speciation, where one species gives rise to a new and distinctly different species. It is one of the processes that drives evolution and helps to explain the diversity of life on Earth.
<h3>hope it will help u in understanding..</h3>
Population of older female elephants different from the younger female elephants is described below.
Explanation:
- THE OLDEST ELEPHANTS wandering Mozambique’s Gorongosa National Park bear the indelible markings of the civil war that gripped the country for 15 years: Many are tuskless. They’re the lone survivors of a conflict that killed about 90 percent of these beleaguered animals, slaughtered for ivory to finance weapons and for meat to feed the fighters.
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Hunting gave elephants that didn’t grow tusks a biological advantage in Gorongosa. Recent figures suggest that about a third of younger females—the generation born after the war ended in 1992—never developed tusks. Normally, tusklessness would occur only in about 2 to 4 percent of female African elephants.
- New, as yet unpublished, research she’s compiled indicates that of the 200 known adult females, 51 percent of those that survived the war—animals 25 years or older—are tuskless. And 32 percent of the female elephants born since the war are tuskless.
- A male elephant’s tusks are bigger and heavier than those of a female of the same age, says Poole, who serves as scientific director of a nonprofit called ElephantVoices. “But once there’s been heavy poaching pressure on a population, then the poachers start to focus on the older females as well,” she explains. “Over time, with the older age population, you start to get this really higher proportion of tuskless females.”
- “The prevalence of tusklessness in Addo is truly remarkable and underscores the fact that high levels of poaching pressure can do more than just remove individuals from a population,” says Ryan Long, a behavioral ecologist at the University of Idaho and a National Geographic Explorer. The “consequences of such dramatic changes in elephant populations are only just beginning to be explored.”
Answer:
yes
Explanation:
as the atrium contracts , blood flows from your right atrium into your right ventricle through the open tricuspid valve. when the ventricle is full, the tricuspid valve shust . this prevents blood from flowing backward into the right atrium while the ventricle contracts
