Answer:
Liquid
Explanation: It can't be gas because gases are all around us and we can still see light. For solids it can't even move through a solid. Ex: If you're in a solid dome made of rock you can't get any light through. Let me know if I'm right!
Answer:
45degres
Explanation:
A projectile travels the farthest when it is launched at an angle of 45 degrees.
The time taken by the swimmer was 1 hour.
Why?
Since the swimmer is maintaining an angle of 150° while he was swimming, there were two components of the speed (horizontal and vertical). If we want to calculate the time taken by him to cross the river, we need to calculate the vertical speed and consider that the flow's speed is compensated by his horizontal speed.
We can calculate both components of the speed using the following formula:

Now, calculating we have:

Therefore, we have that the horizontal speed is compesating the flow's speed while his vertical speed is used to cross the river which is 1 Km wide.
Hence, we have that the tame taken is:

Have a nice day!
Answer:
The process is a mechanism known as mantle convection
Explanation:
Mantle convection is the driving mechanism for plate tectonics, which is the process ultimately responsible for producing earthquakes, mountain ranges, and volcanos on Earth.
This mechanism occurs in four different patterns
- Collision: this is the shoving together of two continental plates
- Subduction: this is the plunging of one plate beneath another
- Spreading: this is the pushing apart of two plates
- Transform faulting: this occurs when two plates slide past each other