Weegy: Oxygen levels started to decline from 35 percent down to today's levels about 95 million years ago.
User: why is the horseshoe crab an example of a living fossil?
Weegy: The horseshoe crab is an example of a living fossil because it hasn't changed since it first appeared on Earth.
User: what are two gases that escaped earths atmosphere during early formation?
Weegy: H2 and He were the two gases that escaped earths atmosphere during early formation.
User: during the carboniferous period, plants and and animals grew very large due to high concentration of
Weegy: During the Carboniferous period, plants and animals grew very large due to high concentration of oxygen in the atmosphere.
User: which principle states that rock fragments in sedimentary layers must be older than the surrounding sediments
Weegy: The Principle of inclusions states that rock fragments in sedimentary layers must be older than the surrounding sediments.
User: what's responsible for causing eutrophication in waterways
Weegy: 1+1=2
User: what is the greenhouse effect
Weegy: The greenhouse effect is a warming of Earth's surface and the air above it, caused by gases in the air (chiefly water vapor and carbon dioxide) that trap energy from the Sun.
User: which process(es) cause(s) thick sediment layers to accumulate along the boundaries of a continent
Weegy: Subduction causes thick sediment layer to accumulate along the boundaries of continental and oceanic plates.
User: which material forms in sediments and is precursor to hydrocarbons
Weegy: Kerogen is a material which forms in sediments and is a precursor to hydrocarbons.
User: what's one cause of the heat island effect
Weegy: One cause of the heat island effect is Lower albedo in urban areas.
User: how does miller-urea experiment fall short of demonstrating that life can arise from inorganic molecules
Weegy: The Miller-Urey experiment falls short of demonstrating that life can arise from ...
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