2. which statement about compounds is true?
a. compounds are chemical substances
b. compounds form between two or more elements
c. both a and b
d. none of the above

Which statement best describes the relationship between an allele and a gene? question 1 a. an allele is a variation of a gene that can be expressed as a phenotype. b. an allele is the part of a gene that attaches to messenger rna molecules. c. an allele is a segment of a dna molecule that controls replication of a gene.