<u>Answer:</u>
Common ancestor is the main factor that determines that all terrestrial animals are quadrupedal.
<u>Explanation:</u>
- Phylogeny means the evolution of the organisms or genetically related organism and how they are related.
- The study of phylogeny is called as phylogenetics. Terrestrial means those who live on land.
- Mammals are one who gives birth to their offspring directly. They are generally warm-blooded, breath air.
- Studying each state of the ancestor and also tracing the organism characteristics during evolution.
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.
C. From carbon dioxide in the atmosphere
<span>Receptors in muscles provide the brain with information about body position and movement. The brain controls the contraction of skeletal muscle. The nervoussystem regulates the speed at which food moves through the digestive tract.</span>
