I believe it’s the Carboxyl group but confirm online. Hope this helped :))
Answer:
Sorry , I don't know but still I will take points .
Answer:
Eath's crust
Explanation:
Silicon dioxide (SiO2) and aluminum oxide (Al2O3) are the two most abundant compounds in the Earth's crust. This explains why oxygen, silicon, and aluminum are the three most abundant elements in the crust.
The most abundant compound in the universe is water.
