Answer:
Option A, Hormones are controlled by a feedback loop; information about a system is sent back to the controller of the system to improve its function.
Explanation:
Negative feedback loop controls the hormone production and release. This is done by eliciting the release of substances till a certain level after which the stop signal is activated thereby preventing further release. By this method, concentration of hormones in blood is maintained within the narrow range.
For example – Thyroid hormones is released when the anterior pituitary signals the thyroid. This continues till the hormones in the blood reach the threshold level. Once the threshold level is reached, hypothalamus receives a feedback and then signals anterior pituitary to inhibit further signaling to the thyroid
Hence, option A is correct
Answer:
Explanation:
The tricuspid valve separates the right atrium from the right ventricle carrying deoxygenated blood from right atrium to right ventricle
The mitral/bicuspid valve separates the left atrium from the left ventricle carrying oxygenated blood from left atrium to left ventricle
Pulmonary semilunar valves separates the right ventricle from the pulmonary artery preventing bachelor of blood.
Aortic semilunar valves separates the left ventricle from the aorta preventing backflow of blood
The heart and the arteries of a person, both contracts to pump the blood throughout the body. The aorta, which is the largest artery of the human body, pumps the blood from the heart to the entire body of a person. The oxygen-rich blood is pumped out of the left ventricle when its contraction into the aorta, from where it is transported to the whole body.
Hence, the given statement is true.
Answer:
The correct answer is option 2. "Scientists use seismometers to measure the earthquake activity that occurs beneath a volcano. They then predict the eruption of that volcano".
Explanation:
A seismometer is an equipment used by scientists to monitor ground's motion, including the earthquake activity that occurs beneath a volcano. These instruments are useful to predict if a volcanic eruption is imminent. By analyzing the length and strength of the ground's motion occurring during earthquake activity near a volcano, scientist could predict if an eruption is about to take place.
