Who provided x-ray diffraction photographs of purified dna fibers that suggested a helical structure with a consistent diameter of about 2 nm and a complete helical turn every 3.4 nm?

Watson & Crick

Explanation:

They received the Nobel prize for science for their discovery in 1962. Their capacity to be able to represent DNA double helix in 3D was made possible by advancements in the model building- a science that allows three-dimensional structures to be modeled based upon known molecular distances and bond angles.

volcanoes (an event in the geosphere) release a large amount of particulate matter into the atmosphere. these particles serve as nuclei for the formation of water droplets (hydrosphere). rainfall (hydrosphere) often increases following an eruption, stimulating plant growth (biosphere).

the answer is "a.) well–developed vascular system."

explanation: