Answer:
Explanation:
Scientists have converted skin cells from healthy adults directly into motor ... human motor neurons growing in the lab would be a new tool since researchers can't ... Scientists working to develop new treatments for neurodegenerative ... And importantly, avoiding a stem cell state allows the resulting motor ...
Answer:
they do not evolve, they are birds
Explanation:
Answer:
B) The "lub-dub" sound originates from blood turbulence through the heart.
Explanation:
The systole and diastole in the heart produce the lub and dub sound in the heart.
The systole represents the contraction of both left and right ventricles and pumps the blood to the body and the right ventricle to the lungs. This involves the opening and closing of the valves. The closing of the atrioventricular valves produces lub sound.
At the end of the systole or ventricular contraction or when the blood has been pumped to the aorta and the pulmonary valves then the semilunar valves present in the aorta and pulmonary closes. This produces a sound dub.
Therefore,lub dub is associated with the physical contraction of the heart but not the turbulence of the blood.
Thus, the selected option is the correct answer.
When
the morning announcements call for you to rise to recite the pledge of
allegiance, the signal to stand up on your feet is sent by the somatic nervous system. The somatic nervous system is <span>part of the peripheral nervous system. Its functions are : </span><span>voluntary movement of the muscles and organs and reflex movements. So, the signal to stand up on our feet in the morning is movement of the organs sent by this system. </span>
Answer:
Aside from reducing fish stocks, unsustainable fishing practices can have other negative impacts on the marine environment. For example, some fishing techniques such as dredging and trawling can cause widespread damage to marine habitats and organisms living on the sea floor.
