Decide which element probably forms a compound with oxygen that has a chemical formula most and least similar to the chemical formula of the compound formed by oxygen and cesium.

Most similar   -----  Lithium

Least similar   ----  Nitrogen

Explanation:

Cesium is an element on the periodic with the atomic number 133. It lies in group 1 (i.e., the alkali metals) and period 6 on the periodic table. The oxidation state of group 1 metals is +1. Cesium forms an oxide with oxygen as  .

The most similar compound to this chemical compound is Lithium because Lithium happens to be in the same group one metal with Cesium and forms the compound with the oxygen

The least similar compound nitrogen due to fact that it is an oxide that is covalent in nature and lies between-group 3 -17  to form an with oxygen.

c- cold periods in earth's history during which glaciers covered much of the surface.

explanation:

i think it's c. i'm not sure but i think so.