Aball of clay sinks when placed in water. the same piece of clay floats if it is made into the shape of a boat.
why does the clay float when made into the shape of a boat?
a. the clay is less dense when stretched into the shape of a boat.
b. the buoyant force is greater on the clay when it has a spherical shape.
c. the boat shape displaces a greater volume of water than the ball shape.
d. the weight of the clay boat is less than the weight of the clay ball.

The correct answer is definitely d. The weight of the clay boat is less than the weight of the clay ball.
In such situations, the point that we should take as a basis to resolve a question is weight. If the weight of clay is less than that of a clay ball, the clay will float.

An  atom  (ours, not carroll's) consists of a positively charged  nucleus, surrounded by one or more negatively charged particles called  electrons. the positive charges equal the negative charges, so the atom has no overall charge; it is electrically neutral. most of an atom's mass is in its nucleus; the mass of an electron is only 1/1836 the mass of the lightest nucleus, that of hydrogen. although the nucleus is heavy, it is quite small compared with the overall size of an atom. the radius of a typical atom is around 0.1 to 0.25 nanometres (nm), whereas the radius of a nucleus is about 10-6  nm.  *  if an atom were enlarged to the size of the earth, its nucleus would be only 200 feet in diameter and could easily rest inside a small football stadium.read more on -

26.4 is about the right time