Answer:
1. A gene is a segment of DNA that codes for a protein or RNA; alleles are alternate forms of a gene.
Explanation:
DNA is the genetic material and stores genetic information. A stretch of DNA that codes for a specific protein is called a gene. Transcription of a gene forms mRNA which in turn is translated into a protein. Alleles are the alternative forms of a gene. A gene may have two or more alleles. However, diploid organisms can have two alleles for a gene which in turn are present on a particular locus on homologous chromosomes. For instance, I^A, i and I^B are the alleles for the ABO blood type in humans.