<span><span>a. </span>Reproducing</span>
f. obtaining
energy
d.
maintaining structure
Why do these
three illustrate the great challenge for every species.
<span><span>
1. </span>Reproduction, is as vital for an entire race to survive. It prolongs
their generation onwards and offspring to the next centuries to pass by.</span>
<span><span>
2. </span>Obtaining energy. In both humans and animals, even plants is a
challenge because these creatures need to work in order to obtain these need
resource from food –preys.</span>
<span><span>
3. </span><span>Maintaining structure. For the living organisms to still exist they
need to keep themselves intact. Combating diseases and having nutrition. This is
a by-product of having energy. </span></span>
Th RECTUM is placed at the lower end of the large intestine.
Answer:
A presynaptic neuron knows when and how much of a certain neurotransmitter it has to release into the synapse by the frequency of the action potential.
Explanation:
Two nuerons connect to each other through synapse. When an action potential, or nerve impulse, arrives at the axon terminal, it activates voltage-gated calcium channels in the cell membrane, then the calcium which is present in hi highconcentration outside the neuron than inside, rushes into the cell. The Calcium then allows synaptic vesicles to fuse with the axon terminal membrane, releasing neurotransmitter into the synaptic cleft.
The nuerotransmitter than binds to the receptors at the post-synaptic cleft and causes the opening or closing of the channels, hence, depolarizing or hyperpolarizing the cells.This can produce a change in the membrane potential—voltage across the membrane of the receiving cell.
Answer:
The correct answer is 4.ecosystem.
Explanation:
An ecosystem is a system, that is, a set of elements that interact with each other, in which such elements are: physical environment, living beings and their interactions (predator-prey, parasite-host, competition, symbiosis, pollination, distribution of seeds , etc.) The interrelation between living beings (competition, parasitism, etc.) occurs through cycles of matter and energy flows on which the functioning of the entire ecosystem depends.
Air pollution. Cleaner burning than other fossil fuels, the combustion of natural gas<span> produces negligible amounts of sulfur, mercury, and particulates. Burning</span>natural gas does<span> produce nitrogen oxides (NOx), which are precursors to smog, but at lower levels than gasoline and diesel used for motor vehicles.</span>
