Please help I am in need Which of the following sequences of elements would all have four valence electrons?

A.) B, Si, As, Te

B.) C, Si, Ge, Sn

C.) O, S, Se, Te

D.) Ga, Ge, As, Se

Between 2014 and 2016, more than 25,000 children in flint, michigan, drank water that was contaminated with lead from lead pipes. during this time, the city claimed the water was safe to drink. which of these actions could the city have taken to ensure that the drinking water was free from lead?

Why is silver chloride is an ionic compound

This chart lists four kinds of polymers and their sources. what can be known about all four polymers, despite their differences? they come from living things. they share ionic carbon bonds. they are at least 100 monomers long. they are made of repeating subunits.