7th grade science unit 12

The largest mass extinction in the Phanerozoic eon happened at the end of the  

• Mesozoic Era (during the Cretaceous period) 
• Paleozoic Era (during the Permian period) 
• Cenozoic Era (during the Quaternary period)
• Late Proterozoic Era (during the Precambrian period 

What type of life was most common during the Paleozoic Era?  

• Marine life
• Reptiles
• Mammals
• No life

What type of life was most common in the Mesozoic era? 

• Marine life
• Reptiles
• Mammals
• No life

What are the main sources of the gasses that first made up the earth's atmosphere?

• Volcanoes and ice-covered comets
• Clouds of gasses in space that the earth passed through
• Hydrogen and helium escaping from the sun and getting trapped in the earth's gravity
• There was no atmosphere until life evolved and began producing gasses.

What type of life was most common in the Cenozoic Era

• Marine life
• Reptiles
• Mammals
• no life

What is the solar nebula?

• The cloud of dust and gas that eventually produced the sun
• The sudden, rapid and intense variation in brightness that occurs on the surface of the sun
• The effect the sun has on the planets that orbit it
• The materials found at the very center of the sun

Before the solar nebula became the sun it

• contracted, began to spin and formed a disc
• expanded from a small mass of material until it reached its present size
• exploded into a huge burning mass of carbon
• completely disintegrated  

During which era did life start to move from water to land?

• Cenozoic era
• Mesozoic era
• Paleozoic era
• Precambrian era

How long ago did our solar system form?

• 5 billion years ago
• 5 million years ago
• 50 thousand years ago
• It has always existed

How did planets form?

• Large round objects broke off from the sun and began to orbit around it
• planets came from other areas of space but when they got to close to the sun they began to orbit it
• materials in the disc surrounding the sun started colliding with other material in the same solar orbit and fused into a planet
• One large solar body circling the sun broke into several pieces