answer each 1. Earth is the third planet from the Sun. It is the only planet in the solar system to have just the right conditions for life as we know it to exist. One of these conditions is the distance from the Sun. The others are the presence of an atmosphere, a magnetic field, and liquid water. They make Earth unique.
2. Earth is located 93 million miles away from the Sun. This is the right place in the solar system to have temperatures which support life. If Earth were any closer to the Sun, the temperatures would rise. If Earth were too far away from the Sun, temperatures would be too cold to support life as we know it.
3. Another unique condition that makes life possible on Earth is the presence and composition of the atmosphere. In order for a planet to have an atmosphere, there has to be a gravitational force strong enough to hold it there. There are planets in the solar system which have no atmosphere. One that can support life is even more special. The atmosphere is all of the air and gases that surround Earth. It rises 600 kilometers above Earth's surface. This mixture of air and gas is composed of 78% nitrogen, 21% oxygen, and 1% argon and carbon dioxide. This mixture of gases helps keep the temperature stable and cool. This mixture also has the oxygen that most life forms need.
4. The presence of a magnetic field is also necessary to support life. The magnetic field can be thought of as a giant bubble. It rises just above the atmosphere. It shields Earth from harmful solar particles that stream from the Sun. Life would not be possible without this protection.
5. The fourth condition that allows life to exist on Earth is the presence of water. Water is necessary for all living things. Earth is the only planet in the solar system with liquid water. Three-fourths of Earth's surface is covered in water. Like the atmosphere, oceans help keep the temperatures on Earth stable. Water can exist in all three states of matter on Earth. It can be a liquid in the form of water. It can also exist as a solid in the form of ice, or a gas in the form of water vapor.
6. Conditions for life are exactly perfect on Earth. Our planet has an atmosphere, magnetic field, liquid water, and just the right distance from the Sun. Earth is a unique planet in our solar system.
QUESTION 1
Examine the graph which plots the average surface temperature of the planets by their distance from the Sun. The data point for Earth has been circled. What would happen if Earth were located at the position marked by the star?
OPTIONS
The conditions on Earth would be suitable for life because the temperatures would not change.
The conditions on Earth would be too cold to support life as we know it on Earth.
The conditions on Earth would be exactly the same.
The conditions on Earth would not be suitable for life because the temperatures would be too high.
QUESTION 2
Which of the following is an accurate summary of the passage?
OPTIONS
The magnetic field is a bubble around Earth.
Water exists in three states: water vapor, carbon dioxide, and ice.
The atmosphere is held in place by gravity and rises 600 kilometers above Earth into space.
Life exists on Earth because of its distance from the Sun, and the presence of an atmosphere, a magnetic field, and liquid water.
QUESTION 3
Why is Earth’s magnetic field important to the survival of life?
OPTIONS
The magnetic field shields Earth from harmful particles that stream from the Sun.
The magnetic field is a bubble around Earth.
The magnetic field holds in all the oxygen, nitrogen, argon, and carbon dioxide.
The magnetic field is only imaginary, and it is not really doing anything for the survival of life on Earth.
QUESTION 4
Complete the following analogy:
atmosphere:air for breathing _______:protection from Sun’s particles
OPTIONS
conditions
magnetic field
water
temperature
QUESTION 5
What favorable characteristics does the atmosphere provide that enables life to thrive on Earth?
OPTIONS
The atmosphere helps keep temperatures stable, and it contains oxygen.
The atmosphere is held in place by gravity and rises 600 kilometers above Earth into space.
The atmosphere is held in place by gravity and has a magnetosphere.
The atmosphere allows for the existence of water in all three states of matter.