What evidence suggests when oxygen gas first
became a significant part of Earth’s
atmosphere?
a. multi-celled microorganisms that breathed
oxygen
b. fossils of dinosaurs
c. molten rock from volcanoes that were rich
in oxygen
d. rusty rocks indicating oxidized iron
e. the presence of water vapor in the
atmosphere
D
You might also like to view...
Which type of epithelium functions in diffusion?
a. simple squamous epithelium b. stratified squamous epithelium c. cuboidal epithelium d. simple columnar epithelium e. simple pseudostratified columnar epithelium
All types of matter and energy are included in the study of the natural world
a. true b. false
Pollination and fertilization are essentially the same process. If pollination occurs, fertilization will follow quickly.
Answer the following statement true (T) or false (F)
Which of the following statements is not true of protists?
A. Moisture is absolutely essential to their existence. B. They make up a substantial fraction of the marine plankton. C. They are not known to cause diseases of humans. D. Most are free-living.