Could you please define the words contributors and span in the following text in a very very simple English

Question

History of medicine and their use: Plants have been collected cultivated harvested for the healing properties and used for the treatment of illness for centuries. Contributors to the current knowledge about drugs span the globe.

Please don't simplify whole passage. I need a simplified definition of the highlighted words so that I could research about the meaning of passage on my own. A million thanks in advance. I looked them up in the dictionaries but didn't manage to associate them with this context

Answer 1

Contributors: definition 1: people who add to something (in this case knowledge).

Span: See definition 13; it means to extend everywhere. "Span the globe" means they are from all around the world.

Answer 2

Contributors (noun, plural)
People who add to a collection, especially to increase the collection's size, or improve its value.
In this case, the text is likely referring to doctors, nurses, healers.

Span (verb)
To extend across a distance or area. To fully cover the distance.

In other usage, "span" can be a noun, meaning distance, length, magnitude, or even an object such as a beam, bridge or girder.