Biotic natural resources also include fossil fuels such as coal and petroleum which are formed from organic matter that has decayed. Abiotic: these resources come from non-living and non-organic material. Examples of these resources include land, fresh water, air, and heavy metals (gold, iron, copper, silver, etc.).
Answer:
A plausible hypothesis is that deleterious germline mutations in sperm cells are removed by natural selection since sperms have to compete to fertilize the egg
Explanation:
Sperm cells need to travel through the cervix in order to reach the uterus and fertilize the egg. During this process (which is called 'fertilization'), approximately 300 million sperm cells have to compete in a race to reach an egg. During fertilization, the majority of sperm cells die off quickly because male germinal cells carry mutations that lead to abnormalities (e.g., many sperms have double heads, others no tail, etc). The sperm cells are considered to be physiologically weak because their normal functions can be easily disrupted by mutations and, simultaneously, they are under strong selective pressure to be selected during the sperm race. In consequence, deleterious germline male mutations are expected to be eliminated by natural selection, thereby sperms are selected before fertilization so only the strongest ones can compete in the race to fuse with the egg cell and thus develop one zygote.
Answer:
The change in conformation of voltage-gated calcium channels in the axon terminal membrane causes the increase in cytosolic calcium that triggers the fusion of secretory vesicles to the membrane and the release of neurotransmitters into the synaptic cleft.
Explanation:
- As the calcium concentration becomes less in the cytosol, it allows calcium ions and functions it as a secondary messenger in the calcium signaling process.
- During the action potential, or any nerve impulse, that arrives at the terminal of axon, the activation of voltage-gated calcium channel is carried. This activation is done in the cell membrane.
- Calcium ion has the key responsibility for the triggering of synaptic vesicles to release the neurotransmitters.
Answer:
Homo sapien
Explanation:
Homo is the genus name
sapien is the species name