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:
a video that shows penguin species that have different mating dances
Explanation:
The question is incomplete as it does not have the options which are:
- a video that shows a large river that has penguin populations on both sides
- a video that shows penguin species that have different mating dances
- a video that shows a penguin that is laying eggs
- a video that shows penguins in a tidal pool and an open ocean
Answer:
a video that shows penguin species that have different mating dances
<em><u>The reproductive isolation is the factor which allows the species to evolve and form a new species, therefore, this factor is used to describe a species.</u></em>
<em><u /></em>
<em><u>The reproductive isolation refers to a mechanism in which the species are isolated to not interbreed with the individual of other species. The reproductive isolation could be due to behavioural, psychological, physical or genetic differences. evolved as an adaptation.</u></em>
<em><u /></em>
<em><u>In the given cases, the penguin species which shows different mating dances is considered to be reproductively isolated as the different dance rituals evolved as behaviour to prevent them from mating.</u></em>
<em><u /></em>
<em><u>Thus, the selected option is correct.</u></em>
<h3>
<em><u /></em></h3>
Answer:
Magnetite is black or brownish-black with a metallic luster, has a Mohs hardness of 5–6 and leaves a black streak.
