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:
Yes, swollen lymph nodes are more common than some might think.
Explanation:
The medical terms for swollen lymph nodes are adenopathy or lymphadenopathy.
Lymph nodes play a vital role in fighting off sickness in the body. They act as a filter, trapping bacteria and viruses before they can spread too far.
Lymph nodes <em>typically</em> swell up as a response to bacteria or viruses. Though cancer can be a factor in swelling, it is very rare. Most commonly they are felt right below the corner of the jaw, in the neck. Yet, they are not only in the neck; they are all throughout the body. When they are swollen, they might feel tender or even painful.
Answer:
1. Bryofita
2. vascular plants
3. Seed vascular plants (gymnosperms)
4. Angiosperms
Explanation:
1. Bryofita
Around 475 million years ago, the origin of plants was thought to originate from aquatic ancestors (green algae). Adaptation to terrestrial life is proven by the presence of sporopolenin and layered gametangia that protect gametes and embryos. This adaptation occurs in bryophytes which are the first terrestrial plants. Bryofita or mosses develop into various vanations in their group. Most briolites do not have vascular tissue (water from the environment is diluted and absorbed by the SD, but some briophytes have water-carrying vessels.
2. Vascular plants
Around 400 million years ago, the evolution of plants was marked by the diversification of vascular plants (vascular plants). These early vascular plants are seedless plants, for example in the types of ferns seria into other groups of seedless plants.
3. Seed vascular plants (gymnosperms)
Plant evolution begins with the appearance of seeds, which are structures that protect the embryo from drought and the threat of environmental change. The emergence of these seed plants accelerated the expansion of plant colonization on land. Plant seeds consist of embryos and food reserves that are protected by a cover. Seed vascular plants appeared about 360 million years ago with the appearance of Gymnosperms. Gymnosperms consist of conifers with a variety of types. Conifers and ferns dominate life in the months between more than 200 million years.
4. Angiosperms
About 130 million years ago marked the emergence of flowering plants that have a somewhat reproductive structure
complicated where the seeds are protected by a room called the ovary.Because the seeds are protected in such a way that this group discusses closed seed plants or Angiosperms
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About African elephant species and their relationship to the environment brainly.com/question/12630439#
Details
Class : Junior High
Subject : Biology
Keywords
- Plant
- Plant Evolution
