End-to-end encryption and privacy controls.
Message and call for free* around the world.
Group conversations made simple.
Say it with stickers, voice, GIFs and more.
Reach your customers from anywhere.
https://123deta.com/document/yjdmoe5y-分子原子原子核分子電子同じ元素陽子数が同じで中性子数の違うものを同位体という今日知られている同位体は.html