Answer:

Explanation:
The tension in a cable is given by:

Where
is the mass density of the cable and v is the speed of the cable's pulse. These values are defined as:

The pulse makes four trips down and back along the cable, so 

Replacing (2) and (3) in (1), we calculate the tension in the cable:

Answer:
You should have noticed that the number of atoms in the reactants is the same as the number of atoms in the product. The number of atoms is conserved during the reaction. However, you will also see that the number of molecules in the reactants and products are not the same.
Answer: Frequency
Explanation: The velocity of a wave is the product of wavelength and frequency. That is to say:

Hence, the frequency associated with the tsunami is needed to calculate the velocity.
The waves as it gets closer
All of these are necassary for photosynthesis. So your answer would be all of the above.