Antimater has positively charged electrons (positrons) and negatively charged protons (antiprotons). Its neutrons are antineutrons made of a positron and antiproton.
So just the charges are swapped around.
Charges interact with electric fields.
Gravity is related to mass. It doesn't matter whether the bulk of the mass comes from negatively or positively charged particles.
Of course, antimatter has opposite electrical attraction. If an antimatter plastic comb attracts antimatter styrofoam crumbs, those crumbs will be repelled by the matter plastic comb (luckily for them).
> Its neutrons are antineutrons made of a positron and antiproton.
Neutrons are made of on up quarks and two down quark (and a lot of gluons).
Antineutrons are made of on up antiquarks and two down antiquark (and a lot of gluons).
There are no (anti)protons or (anti)electrons inside (anti)neutrons.
> Of course, antimatter has opposite electrical attraction.
Nitpicking: attraction -> charge
> If an antimatter plastic comb attracts antimatter styrofoam crumbs, those crumbs will be repelled by the matter plastic comb (luckily for them).
IIRC the charge in the comb induces a charge in the crumbs. If the charge of the comb is X, the -X charges move closer to the comb, and the X charges move far away. And that those displaced charges create a dipole that is attracted to the comb.
So I think the anti-comb would attract the normal-crumbs and create a huge explossion.
So just the charges are swapped around.
Charges interact with electric fields.
Gravity is related to mass. It doesn't matter whether the bulk of the mass comes from negatively or positively charged particles.
Of course, antimatter has opposite electrical attraction. If an antimatter plastic comb attracts antimatter styrofoam crumbs, those crumbs will be repelled by the matter plastic comb (luckily for them).