Answer:
a. heart development.
Explanation:
As the third week of fetal development starts, the process of formation of blood vessels begins. Also, the splanchnic mesoderm in the head end of the embryo forms heart on days 18 and 19. Since it develops heart, this part of the mesodermal cells is called the cardiogenic area. The underlying endoderm sends the induction signals to these mesodermal cells to form a pair of endocardial tubes that gradually develop into a single primitive heart tube.
This primitive heart begins to beat by the end of the third week of development. Therefore, any drug that affects fetal development during the first 20 days of the pregnancy might affect the development of the heart.
Diluting an acid decreases the concentration of H+(aq) ions , which increases the pH level of the solution towards 7 , making it less acidic . However , the pH level of an acidic solution cannot become greater than 7 , because the water you add to dilute it is not alkaline .
<span>enzymes are resuable as they are biologically catalyst which speeds up the rate of a reaction without being chemically changed themselves. However, if the enzyme is to be denatured under unfavourable conditions (extreme temperatures, extreme pH), the enzymes may not be reusable once denatured.</span>
Answer:
First the proprioceptors found in the tissues will capture tissue damage and the presence of a continuity solution in the skin, then these receptors will activate the afferent pathway, which is the pathway of pain, which is sensory.
This stimulus that ascends to the central nervous system activates the "flight" mechanism in the face of pain (it is also known as the withdrawal mechanism).
It is in this way that a stimulation is sent to the alpha motor neuron in the form of an action potential as an efferent pathway to the skeletal muscles of the foot and the damaged leg, so that an automatic and involuntary muscle contraction is generated in a matter of millisemas of second after the damage, so the foot is removed from the damage area.
Explanation:
The withdrawal mechanism is a reflex that the human acquires before pain, that is why it is the muscular contraction is automatic and fast once the pain occurs.
So as a summary: 1 - the proprioceptors of the damaged tissue are activated 2- the signal of tissue damage rises as afferent to the CNS 3- the CNS responds by activating a signal that will be sent by interneuronal connections to the alpha motor neuron 4- the signal arrives as potential of action to the alpha motor neuron that innervates the muscles of the surrounding area to which it is damaged 5 - the muscles contract, generating the withdrawal of the limb.