How did scientists discover the common structure of cells?

What does the number 18.9984 represent in the image?

The variation among individuals, on which natural selection acts

Which of the following statements about polysaccharides are correct? choose all that apply.cellulose is a linear, unbranched polymer of glucose monomers.starch is typically more highly branched than glycogen.cellulose is a major component of both plant and animal cells.glycogen is a storage form of glucose in animal cells.glycogen is the most abundant organic compound on earth.starch and cellulose are found in plants.