The gravitational force between two students sitting beside each other on Earth is

Fgrav. = GM1×M2/R2

Explanation:

Gravitational force is mostly related

to planetary bodies by Newton's law of gravitation which states that the gravitional force is proportional to the product of the mass of the object and inversely proportional to the square of the distance between them.

Hence in this case the Gravitational force,

Fgrav. = GM1×M2/R2

M1 and M2 are the mass of the two students and R is their distance apart

G is a constant known as gravitational constant.6.67408 × 10-11 m3/kgs2

an ion is a charged atom or molecule. it is charged because the number of electrons do not equal the number of protons in the atom or molecule. an atom can acquire a positive charge or a negative charge depending on whether the number of electrons in an atom is greater or less then the number of protons in the atom.

real, smaller and upside-down.   so the answer should be b.