Well plants breathe carbon and let out oxygen so it cleans the air, not sure about the energy use...
centrifugal force is a fictitious force. What is happening is that since the earth itself is not a rigid body it will deform when under motion. Although gravity attempts to make the earth spherical, as it is rotating the earth deforms, in such away that it flattens to become an oblique spheroid. This happens as the material at the equator must have a net resultant centripetal force (not centrifugal) which causes its position of equilibrium from the center of the earth to be further away than at the poles as they do not have this force as they are not rotating around the center of mass.
Answer:

Explanation:
given,
wavelength, λ = 50 cm
speed, v = 4 m/s
Amplitude, A = 5 cm
general equation of the wave along x- axis

sign is positive when wave is traveling in negative direction
now,



inserting all the values

Hence, the y-equation of wave is equal to 
At Z ... slowest speed
At Y ... fastest speed
At X ... medium speed
Wherever it is in its orbit, the line from the planet to the Sun smears over the same amount of area every second.
That's Kepler's second law of planetary motion.
The reason this happens is: That's how gravity works. (A better explanation is available, but first you have to be able to twirl calculus and solid geometry in the air on long sticks.)
In physical chemistry, the mean free path is the average distance between the atoms during collision. Its formula is

where d is the diameter of the Nitrogen atom (d = 310 x 10^-7 m), Na is Avogadro's number (Na=6.022 x 10^23), R is the gas constant (8.314 J/mol-K), T is the absolute temperature (T= 20 + 273 = 293 K). Substituting the values,
P = 6.32 x 10^-13 Pascals