(F) Belief in alchemy delayed scientific progress for centuries.
(G) Some of the principles of alchemy are still valid today.
(H) Modern chemistry owes nothing to the achievements of the alchemists.
(J) Though not a science, alchemy is an important part of scientific history.
(K) Most alchemists wanted to produce gold only for their own financial benefit.Most life is fundamentally dependent on
photosynthetic organisms that store radiant energy
from the sun. In almost all the world’s ecosystems and
food chains, photosynthetic organisms such as plants
( 5 ) and algae are eaten by other organisms, which are then
consumed by still others. The existence of organisms
that are not dependent on the sun’s light has long been
established, but until recently they were regarded as
anomalies. Over the last twenty years, however,
( 10 )research in deep sea areas has revealed the existence of
entire ecosystems in which the primary producers are
bacteria that are dependent on energy from within the
earth itself. Indeed, growing evidence suggests that
these subsea ecosystems model the way in which life
( 15 )first came about on this planet.
The first of these unique chemosynthetic
ecosystems was discovered in 1977 by a small
research submarine investigating the Galapagos Rift, a
volcanically active area 7,000 feet below the surface of
( 20 )the eastern Pacific Ocean. At a boundary between
adjacent plates in the earth, scientists found a
surprisingly congenial environment for life. They
discovered that water was seeping down through
cracks in the ocean floor, being heated by the volcanic
( 25 )rocks, and rising again to create an oasis of warmth in
the near-freezing waters. Moreover, under conditions
of extreme heat and pressure, chemical reactions were
taking place that supplied sufficient energy for
“chemosynthetic” bacteria to develop. In this
( 30 )ecosystem and others discovered since, bacteria
become the primary producers in the ecosystem by
transforming chemicals into compounds that can serve
as nourishment for more complex forms of life.