Botany, the study of plants, occupies a peculiar position is the history of human knowledg

e. For many thousands of years it was the one field of awareness about which humans had anything more than the vaguest of insight. It is impossible to know today just what our Stone Age ancestors knew about plants, but from what we can observe of preindustrial societies that still exist, a detailed learning of plants and their properties must be extremely ancient. This is logical. Plants are the basis of the food pyramid for all living things, even for other plants. They have always been enormously important to the welfare of peoples, not only for food, but also for clothing, weapons, tools, dyes, medicines, shelters, and a great many other purposes. Tribes living today in the jungles of the Amazon recognized literally hundreds of plants and knew many properties of each. To them, botany, as such, has no name and is probably not even recognized as a special branch of knowledge at all.

Unfortunately, the more industrialized we become the farther away we move from direct contact with plants, and the less distinct our knowledge of botany grows. Yet everyone comes unconsciously on an amazing amount of botanical knowledge, and few people will fail to recognize a rose, an apple, or an orchid. When our Neolithic ancestors, living in the Middle East a- bout 10,000 years ago, discovered that certain grasses could be harvested and their seeds planted for richer yields the next season, the first great step in a new association of plants and humans was taken. Grains were discovered and from then flowed the marvel of agriculture, cultivated crops. From then on, humans would increasingly take their living from the controlled production of a few plants, rather than getting a little here and a little there from many varieties that grew wild and the accumulated knowledge of tens of thousands of years of experience and intimacy with plants in the wild would begin to fade away.

Which of the following assumptions about early humans is expressed in the passage？

A．They probably had extensive knowledge of plants

B．They thought there was no need to cultivate crops.

C．They did not enjoy the study of botany.

D．They placed great importance on the ownership of property.