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.
<u>Answer:</u>
The “wheelchair belt” mechanism is the most important mechanism to have on the wheel chair.
<u>Explanation:</u>
- As the patient have very poor control over his trunk so a belt will be perfect to prevent him from falling out of the wheelchair anytime.
- The other options doesn’t make much of important sense than a belt for the patient with muscular dystrophy needs, especially when lost control over the extremities.
- The wheelchair belt will help him in staying in the wheelchair freely without risk of falling off.
The other biologists and scientists thought his theories were bogus