Answer:
The actual elevation angle is 12.87 degrees
Explanation:
In the attachment you can clearly see the situation. The angle of elevation as seen for the scuba diver is shown in magenta, we conclude that
.
Using Snell's Law we can write:

,
Let's approximate the index of refraction of the air (medium 1 in the picture) to 1.
We thus have:

. Calling
the actual angle of elevation, we get from the picture that
I could make a poem for you if you actually gave the words...... what 10 words do i need to incorporate???☹︎
The center of mass is given with this formula:

Velocity is:

So, for the velocity of the center of mass we have:

In our case it is:
C. Sugars dissolved in water
Answer:
Microlensing.
Explanation:
This techniques is called Microlensing.
Microlensing is a method of gravitational lensing where light from a backdrop point of origin is curved to develop distorted, numerous and/or lightened images by the gravity field of a foreground lens.
This method is very effective in discovering planets that are far-far from earth.It is actually an astronomical effect that was predicted by Albert Einstein's general theory of relativity.