Answer:
Explanation:
Acetylcholine (ACh) is an organic chemical that functions in the brain and body of many types of animals (and humans) as a neurotransmitter.
Neurotransmitter is a chemical message released by nerve cells to send signals to other cells, such as neurons, muscle cells and gland cells.
After a neurotransmitter molecule has been recognized by a post-synaptic receptor, it is released back into the synaptic cleft. Once in the synapse, it must be quickly removed or chemically inactivated in order to prevent constant stimulation of the post-synaptic cell and an excessive firing of action potentials.
Some neurotransmitters are removed from the synaptic cleft by special transporter proteins on the pre-synaptic membrane. These transporter proteins carry the neurotransmitter back into the pre-synaptic cell, where it is either re-packaged into a vesicle and stored until it is once again needed to transmit a chemical message, or broken down by enzymes.
Answer:
C
Explanation:
It's pretty simple really, just find the <em>Benefit</em>. Pollution is definitely a harmful effect, disease is also not a benefit, and depletion of fish population is bad, so easing demand on commercial fisheries is the answer
Answer:
c. flows through... are recycled in
Explanation:
In an ecosystem, energy gotten from the sun by plants flows through the ecosystem from one trophic level to another, as the energy in is transformed from one form to another via nutrition.
On the other hand, chemical elements in the form of nutrients are recycled and made available to primary producers when decomposers in the ecosystem to break down organic matter. During decomposition, energy is released. Several nutrient recycling process have feedback mechanisms that ensures chemical elements are recycled back into the ecosystem as they are being used up by organisms.
Biologists think that endosymbiosis gave rise to mitochondria before plastids partly because: (All eukaryotes have mitochondria whereas many eukaryotes do not have plastids)
Answer: alternative D.
Explanation: For the DNA to have the double strand structure, it is necessary to copy the sequence of the existing DNA strand in a complementary sequence of nucleotides, forming hydrogen bonds between them. The mRNA also uses this strategy when reading the DNA strand during the transcription, in order for the translation to begin.
