What is not a requirement of learning? thinking observing being taught waiting?

The answer is: waiting.

Learning is a complex process of a universal nature in the human kind. As such, it is present in every developmental stage of human beings; therefore it does not require any process of expectation of waiting. Being a complex process, it involves many of the mind´s faculties, like thought, reasoning, experience, sensation, and perception, and it can be greatly enhanced through proper pedagogical methods.

a.indigo and cochineal

b.animal hides

c.silver and gold

e.cacao beans and sugarcane