How did diseases involving metabolic pathways lead to hypotheses about the nature of genes

Which element is used in photosynthesis found in atmosphere and fixed by bacteria?

How do accessory pigments chlorophyll?

Some tools have graduations to show multiple measurements. for example, a ruler may have graduations for both millimeters and centimeters. when measuring the length of an earthworm, which graduations would allow for the most accurate measurement? millimeters centimeters decimeters meters