Hypothesis: If I put a chocolate bar on the table near a sunny window, it will melt faster. If your independent variable is the placement of the chocolate bar and the dependent variable is the speed at which it melts, what are some controlled variables that one must have during each trial?

Choose the best definition of allele. a. one of several possible versions of a gene, which each produce a different phenotype b. an organism that's purebred for a given trait c. the process of fertilizing a plant with pollen from another plant d. a set of genes that are located on the same chromosome and so are tightly linked