Does the negative mass of antimatter mean that it's gravitationally repelled from stars?

the driving force for diffusion is...?

a) the concentration gradient
b) the negative gradient of the chemical potential
c) the gas constant times the absolute temperature
d) the gravitational coefficient
e) gravitational acceleration

(a) Can the kinetic energy of a system be negative?
(b) Can the gravitational potential energy of a system be negative?Explain.

(a) Can the kinetic energy of a system be negative? (b) Can the gravitational potential energy of a system be negative? Explain.