<h3>Answer</h3>
At a high temperature above 20° oxygen solubility starts to decrease.
<h3>Explanation</h3>
Oxygen, O2 is a very essential component of water as we can see in its chemical formula h2O.
The solubility of oxygen decreases as temperature increases. This means that warmer water will have less dissolved oxygen than does cooler water.
<h3>Other factors that affects oxygen solubility in water</h3>
Salt levels
higher the salt levels in water, lower will be oxygen in it.
Pressure
Water at lower altitudes can hold more dissolved oxygen than water at higher altitudes because dissolved oxygen will increase as pressure increases.
Answer:

Explanation:
As we know that moment of force is given as

now we have


now from above formula we have

here we know that

so we have


To answer that question, we don't care what the highest and lowest
levels of the wave are, or how far apart they are. We only need to be
able to identify the highest point on the wave, and keep track of how
often those pass by us.
You said it takes 4 seconds for a complete wave to pass by.
Through the sheer power of intellect, I'm able to take that information
and calculate that 1/4 of the wave passes by in 1 second.
There's your frequency . . . 1/4 per second, or 0.25 Hz.
Neutrons have a zero charge but consist of mass.