Isotopes of the same element have different
a) positions on the periodic table
b)chemical behavior
c) atomic numbers
d)mass numbers

Organisms within a population must compete for resources to survive

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

How can antibodies "remember" a particular bacterial invader or "antigen" on that invader?