What must happen before la a chemical reaction can begin

The phlogiston theory in the 17th century attempted to explain burning. the theory stated that combustable objects contained a material called phlogiston, a substance without mass, color, odor, etc. after objects burned, the objects were dephlogistonated and were then in their true form. the phlogiston theory was accepted until the 18th century, when lavoisier proved that combustion requires a gas that has mass. phlogiston is considered a) to be scientific knowledge b) not to be scientific knowledge c) to be proven by scientific method d) to be accepted in the modern scientific community

The earth's polarity has switched many times through history as evidence by what wh the earth clorets he has switched many times throughout history as evidence by what

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.