What do some scientists believe led to the increase in the level of oxygen in the atmosphere?
a. the first photosynthetic reactions
b. photosynthetic cells that used water and not H2S as a source of electrons
c. The development of cellular respiration pathways in cells
d. the use of glycolysis in cells
e. photosynthetic pathways that stripped oxygen off of carbon dioxide and retained only the
carbon in subsequent steps
B
You might also like to view...
Why can’t you give type A blood to a type B patient?
What will be an ideal response?
Which of the following is NOT true of horizontal gene transfer?
A. It occurs when genes are transferred from parent to progeny. B. It increases genetic diversity for a species. C. It has important implications for inferring phylogeny. D. It can occur through endosymbiosis. E. It occurs commonly in bacteria.
Why might a soil that has a sufficient concentration of a mineral element, for example, calcium, not have sufficient availability of the element to maximize plant growth rates?
What will be an ideal response?
A gram-positive bacterium suddenly acquires resistance to the antibiotic methicillin. This trait most likely occurred due to acquisition of new genetic information through
A) conjugation. B) binary fission. C) meisosis. D) transformation. E) transduction.