A NASA scientist receives satellite data indicating that a newly discovered planet contains no oxygen gas in its atmosphere. Fro
m this information she concludes that complex multicellular organisms are UNLIKELY to exist on that planet. This is because_______________. a. unicellular organisms consume multicellular organisms when oxygen levels are low
b. other electron acceptors (like iron) are unlikely to be widely available and abundant
c. endosymbiosis requires high oxygen concentrations for evolution to proceed
d. complex multicellular life cannot exist once photosynthesis has evolved
c. endosymbiosis requires high oxygen concentrations for evolution to proceed
Explanation:
Endosymbiosis is an hypothesis which stipulates that complex organelles like mitochondrion and chloroplast evolved as a result of symbiotic relationship between aerobic, single cell prokaryotes in which an aerobic organism ingest an anaerobic organism in an atmosphere containing oxygen.
The oxygen in the atmosphere is like a poison to the anaerobic prokaryote and the ingestion by aerobic prokaryote protects it from the toxic effects of oxygen and in return, the ingested organism offers some benefit to its host resulting in a beneficial relationship.
Hence, the presence of oxygen is important for endosymbiosis and eventual evolution of complex organelles in multicellular organisms.
It tends to happen in capillaries for example in the lungs avioli are coverd in capilarries so to facilitate the diffusion (exchange) of oxygen in to the blood stream and carbon dioxide out of the blood stream
The phreatic zone, or zone of saturation, is the part of an aquifer, below the water table, in which relatively all pores and fractures are saturated with water. Above the water table is the vadose zone.
The area between the top of the water table and beginning of bedrock/impermeable rock is the saturated zone.
