an antiquark

a quark (an elementary subatomic particle which forms matter)

quark cheese

(physics) an antiparticle

a seed / a pit or stone in a fruit / a gamete (reproductive cell such as a spermatozoan or egg) / a lineage, bloodline / an origin, cause / the materials or ingredients from which something is made

physics (as an area of study)

middle child

(physics) meson

physics, the physical aspects of a phenomenon or a system

a particle (body with very small size) / a particle (elementary particle or subatomic particle)