True. Ions can have a positive or negative charge.
Protons are positively charged. Neutrons have no charge. Electrons have a negative charge. Protons and neutrons are in the nucleus. Electrons revolve around the nucleus.
<u>a) Answer: </u>
<em>Number of molecules in 1 mole</em>
<u>Explanation:</u>
a) Whether we take any of the substance among all three of the given substances they will have the same number of molecules in 1 mole of the substance is considered and the value for this will be 
<u>b) Answer: </u>
<em>In the given question </em><em>mass of the substance</em><em> which is </em><em>greatest</em><em> is asked for </em><em>one mole</em><em> and we also know that </em><em>mass of one mole is given by molar mass. </em>
<u>Explanation:</u>
b) It is known that
is the molar mass for oxygen which is greater than that of hydrogen while fluorine has a molar mass of
which on comparison shows that, it is the highest amongst all three.
Answer:
When the animal has eaten food and the blood glucose level in the body increases. The pancreas cells in the body detects the increase in the blood glucose which leads to increase the insulin hormone.
This decreases the blood glucose level in the level. This is how the negative feedback works in the body if the level of glucose increases.
Negative feedback is the way by which the body maintains homeostasis and maintains equilibrium in the body.
<u>Answer:</u> The magnitude rating for an earthquake causing an amplitude 10,000,000 times
is 7.
<u>Explanation:</u>
Richter scale is defined as the scale which expresses the magnitude of earthquake on the basis of the seismograph oscillations.
The equation used to measure the magnitude of an earthquake on Richter scale is:

where
I = amplitude registered on seismograph 100 km away from seismic center = 
= small amplitude
Putting values in above equation, we get:

Hence, the magnitude rating for an earthquake causing an amplitude 10,000,000 times
is 7.