What is a challenge in sending humans to other planets?

• Lack of interest

• Distance and safety

• Too many astronauts

• No planets to explore

Fill in the blank: Our solar system is part of the ______ galaxy.

• Andromeda

• Milky Way

• Whirlpool

• Sombrero

What is the structure of the universe composed of?

• Only planets

• Only galaxies

• Different objects grouped into systems

• Only solar systems.

Which layer of the Earth is rich in oxygen, silicon, and aluminum?

• Crust

• Mantle

• Core

• Surface

Which layer is the densest part of the Earth?

• Crust

• Mantle

• Core

• Surface

Less dense materials formed which layers of the Earth?

• Core and Mantle

• Crust and Core

• Crust and Mantle

• Mantle and Core

What scale does this model represent?

• scaled size or diameter

• scaled distance to the sun

• Scaled gravity

• Scaled motion

Which model below best represents the correct scale sizes of the Sun, Earth, and Moon system?

• 
• 
• 

True or False
The planets are all equally distanced from each other.

• True
• False

Identify and fill in the names of the planets.

b

c

d

f

g

h

e

a

Jupiter

Earth

Uranus

Saturn

Neptune

Mars

Mercury

Venus