Biology
Chemistry
Math
Physics
Earth & Space
100

This organ pumps blood throughout your body.

the heart

100

Water freezes into this state of matter.

a solid

100

A thermometer changes from 10°C to 16°C. The temperature increased by this many degrees.

6 °C

100

This force pulls objects toward Earth.

gravity

100

This planet is closest to the Sun.

Mercury

200

These tiny structures inside plant cells allow plants to make their own food.

chloroplasts

200

This tool is used to measure the volume of a liquid.

graduated cylinder

200

A student runs 200 meters in 40 seconds. What is the student's average speed?

5 m/s

200

This type of circuit has only one path for electricity to travel.

series circuit

200

Earth's seasons are caused by this.

earth's tilted axis

300

This process allows plants to make glucose using sunlight, water, and carbon dioxide.

photosynthesis

300

Vinegar reacts with baking soda to produce this gas.

carbon dioxide

300

A rock has a mass of 180 g and a volume of 60 cm³. What is its density.

3 g/cm³

300

According to Newton's First Law, an object at rest will stay at rest unless acted on by this.

an unbalanced force
300

This type of rock forms when molten rock cools and hardens.

igneous 

400

This body system removes carbon dioxide from your body and brings in oxygen.

the respiratory system 

400

A substance has a density of 8 g/cm³. If its volume is 5 cm³, this is its mass.

40 grams

400

A bacteria population doubles every hour. Starting with 25 bacteria, this is the population after 4 hours.

400 bacteria

400

A ball rolls down a hill. Its potential energy changes into this type of energy.

kinetic energy

400

This type of plate boundary forms deep ocean trenches when one plate sinks beneath another.

convergent boundary (subduction zone)

500

Red blood cells have a biconcave (flattened) shape because it helps them do this more efficiently.

carry oxygen and/or move through tiny blood vessels

500

Atoms form chemical bonds because they become more stable by doing this.

filling their outer shell/valence shell

500

A car travels 150 miles at 50 mph and then 50 miles at 25 mph. This is the total travel time.

5 hours

500

A 2-kg object accelerates at 4 m/s². According to Newton's Second Law, this is the net force acting on it.

8 newtons

500

Lunar eclipses do not happen every month because of this feature of the Moon's orbit.

the moon's orbit is tilted relative to earth's orbit around the sun