Final answer:
The neutral kaon, K0, is composed of a down quark and a strange antiquark (ds). The quark structure of K0 results in a net charge of 0 and a strangeness of -1.
Step-by-step explanation:
The neutral kaon, denoted as K0, has a quark structure composed of a down quark and a strange antiquark (ds). Since the charges of the down quark and strange antiquark are -e/3 and e/3, respectively, the net charge of the K0 meson is 0, which is consistent with it being a neutral particle. The quark composition of K0 is also consistent with its measured strangeness, as the net strangeness of the down quark and strange antiquark is 0 - 1 = -1.