Assign relative priorities to the groups or atoms in each of the following sets:
c. $-$CH(CH₃)₂
d. $-$CH$=$CH₂

The Cahn-Ingold-Prelog (CIP) priority rules are a set of guidelines used to assign priorities to substituents attached to a chiral center in organic molecules. According to these rules, atoms are prioritized based on their atomic number, with higher atomic numbers receiving higher priority. If two atoms are the same, the priority is determined by the next set of atoms in the substituent chain. This system is essential for determining the configuration of stereoisomers.

Chirality refers to the geometric property of a molecule that makes it non-superimposable on its mirror image, much like left and right hands. Molecules that possess chirality typically have a carbon atom bonded to four different substituents, creating two distinct configurations known as enantiomers. Understanding chirality is crucial in organic chemistry, especially in the context of drug design, as different enantiomers can have vastly different biological effects.

Substituent effects refer to the influence that different groups attached to a carbon chain have on the chemical properties and reactivity of the molecule. These effects can be electronic (inductive or resonance) or steric, affecting factors such as acidity, basicity, and stability. Recognizing how substituents interact with each other and the parent molecule is vital for predicting reaction outcomes and understanding molecular behavior in organic chemistry.