An atomic mass unit is equal to
a.
one-half the mass of a hydrogen atom.
b.
one-fourth the mass of a lithium atom.
c.
one-twelfth the mass of a carbon-12 atom.
d.
one-fifteenth the mass of a nitrogen-15 atom.

c.  one-twelfth the mass of a carbon-12 atom.

Explanation: An atomic mass unit ( amu) is defined as of the mass of an atom of carbon with mass number 12 , which is the most abundant isotope of carbon. Thus the carbon-12 atom has six protons and six neutrons in its nucleus.

1 amu is approximately equal to or . The mass of an atom in amu is roughly equal to the sum of the number of protons and neutrons in the nucleus.

amu is used to differentiate between isotopes as they would have different mass.

the moon affects the earth gravitation ally, causing certain motions of that body and also producing tides in its ocean and atmosphere. the tidal wave in our atmosphere is, however, far too minute to be an effective cause in any known meteorological phenomenon.

explanation:

so here is the information for current research:

-nrel's geothermal analysts, scientists, and engineers perform a full range of research from developing advanced methods of locating and accessing geothermal resources to exploring innovative technologies to extract and produce clean energy from the heat of the earth

and here is the information for the technology of geothermal energy:

-it's clean and sustainable

-resources of geothermal energy range from the shallow ground to hot water and hot rock found a few miles beneath the earth's surface, and down even deeper to the extremely high temperatures of molten rock called magma

-almost everywhere, the shallow ground or upper 10 feet of the earth's surface maintains a nearly constant temperature between 50° and 60°f (10° and 16°c)

-geothermal heat pumps can tap into this resource to heat and cool buildings

-a geothermal heat pump system consists of a heat pump, an air delivery system (ductwork), and a heat exchanger-a system of pipes buried in the shallow ground near the building

-in the winter, the heat pump removes heat from the heat exchanger and pumps it into the indoor air delivery system

-in the summer, the process is reversed, and the heat pump moves heat from the indoor air into the heat exchanger

-the heat removed from the indoor air during the summer can also be used to provide a free source of hot water