Which statement about subatomic particles is true?
protons are the only subatomic particles to have charge.
electrons are the subatomic particles with the smallest mass.
neutrons orbit the nucleus of the atom.
subatomic particles all have the same mass.

The second option - electrons are the subatomic particles with the smallest mass.

Both protons and electrons have charge (protons are positive and electrons are negative)

Protons and neutrons both equal 1 amu (atomic mass unit), whereas electrons weigh about 1/1000 amu

Electrons orbit around the nucleus, whereas protons and neutrons are inside of the nucleus

And for the last option, I already answered it

For cyclohexane compounds drawn in a chair conformation:   -axial bonds are vertical  -equatorial bonds are parallel to two bonds within the ring.  thus, as i assume the chair conformation is drawn:   -the x group is in an axial position, as are the five other vertical bonds.  -three axial bonds are on the top face of the ring  -the other three axial bonds are on the bottom face  the position of the second substituent on each ring carbon is equatorial.  gauche groups must be on an adjacent carbon such as carbon 6 and carbon 2, and also gauche groups are rotated by 60 degrees relative to each other.  drawing the newman projections for c1–c2 and c1–c6 aids in visualizing the groups that are gauche to the y group on c1.  click this link and watch some academic videos that may you more understand the topic