Geometric isomers can exist in which forms?

Geometric isomers specifically arise due to restricted rotation around a double bond or within a ring structure, leading to distinct spatial arrangements of atoms or groups in the molecules. The terms "cis" and "trans" are used to describe these arrangements, where "cis" indicates that similar or identical substituents are positioned on the same side of the double bond or ring, while "trans" indicates that they are on opposite sides.

This concept of geometric isomerism is pivotal in understanding the physical and chemical properties of molecules, as these different arrangements can lead to variations in boiling points, solubility, and reactivity. The presence of geometric isomers is prominently featured in alkenes and certain cyclic compounds, making the distinction between cis and trans a critical point of study in organic chemistry.

Other terms listed in the options refer to different types of properties or isomerism that do not pertain to geometric configurations. For instance, "syn" and "anti" refer more to stereochemistry in reactions and do not specifically denote geometric isomers. "Chiral" and "achiral" describe the optical activity of molecules but not geometric arrangement, while "isolated" and "conjugated" discuss types of double bond configurations rather than