How did chargaff and franklin watson and crick discover the structure of dna?

And give a detailed description! scientist observes the boundary between two tectonic plates for a decade and finds that no new volcanoes have formed over the course of her investigation. does this result support the theory of plate tectonics? why or why not?

Aflame cell is at the end of each tubule of the nephridium malpighian tubules kidneys none of the above

Freckles are a dominant trait in humans. both of the girls have the genotype ff for freckles. if either one marries a man with no freckles, what are the chances that their children will have freckles?