It is possible that the earth's moon is a significant factor for life on earth because the moon may have assisted with

a. tidal energy needed for life
b. keeping earth from flying out into space
c. plate tectonics after it collided with earth
d. the evolution of life on earth from sea to land

  A. Tidal energy needed for life

Explanation:  In principle, everything that is created in the universe has its significance and purpose and so is the Earth's natural satellite Moon. The tide is the result of the impact the Moon has on Earth. When forming a tide, where energy is generated, which can, for example, replace the production of electric power by about 20%. This would reduce the production of electric energy generated by combustion of fossil fuels and reduce the emission of harmful gases.

where are the vectors ?

adding a(n) to an electric circuit would increase the magnetic field around a wire;

b. solenoid

a solenoid is a type of electromagnet whose purpose is to generate a controlled magnetic field.

if the purpose of the solenoid is instead to impede changes in the electric current, a solenoid can be more specifically classified as an inductor rather than an electromagnet.