Unit 2 Test Review

Front

Earth's primordial atmosphere, 4.6 billion years ago, was mainly composed of ____.

Back

hydrogen and helium

Front

A rapid increase in oxygen in the atmosphere first occurred about ___ years ago.

Back

2.4 billion

Front

The most abundant gas in the modern atmosphere is ____.

Back

nitrogen

Front

Earth's prebiotic atmosphere_____

Back

contained no oxygen

Front

What factor primarily determines Earth's climate? Options: plate tectonics, atmosphere, energy output from the sun, volcanic activity

Back

atmosphere

Front

In Earth's early history, what brought new substances like ice, carbon-rich rocks, and ammonia to Earth?

Back

bombardment by meteorites, comets, and debris

Front

What is the process called when organisms use energy from the Sun to convert carbon dioxide and water into sugars, which they use as food to grow, in turn releasing oxygen?

Back

photosynthesis

Front

What organisms was responsible for the increase in the concentration of oxygen in Earth's atmosphere? Options: cyanobacteria, stromatolites, dinosaurs, plants

Back

cyanobacteria

Front

What is the layer called that protects organisms on Earth from the Sun's harmful ultraviolet (UV) radiation?

Back

ozone

Front

Where is the most carbon stored on Earth? Options: surface ocean, atmosphere, fossil fuels, deep ocean, soil

Back

deep ocean