MSU ISP 205 Final Exam 2026 | 200 Practice Questions with
Answers & Explanations | Human Biology A+ Study Guide
1. What is the approximate age of the Universe?
- A. 4.5 billion years
- B. 8.7 billion years
- C. 13.8 billion years
- D. 100 billion years
Correct Answer: C. 13.8 billion years
Explanation: The age of the universe has been determined through measurements of the cosmic
microwave background radiation and the expansion rate (Hubble constant). The current scientific
consensus, based on data from the Planck satellite, is that the universe is approximately 13.8 billion
years old.
2. What is the approximate age of the solar system?
- A. 4.5 billion years
- B. 10 billion years
- C. 13.8 billion years
- D. 100 million years
Correct Answer: A. 4.5 billion years
Explanation: Radioactive dating of meteorites and rocks shows that the solar system formed about
4.5–4.6 billion years ago. The sun is also about this age.
,3. What fraction of the solar system's total mass is contained in the Sun?
- A. 50%
- B. 75%
- C. 99.8%
- D. 99.98%
Correct Answer: C. 99.8%
Explanation: The Sun contains about 99.8% of the total mass of the entire solar system. Jupiter
contains most of the remaining 0.2%.
4. Which planet is moving more slowly around the Sun?
- A. Mercury
- B. Earth
- C. Mars
- D. Jupiter
Correct Answer: D. Jupiter
Explanation: According to Kepler's third law, planets farther from the Sun have longer orbital
periods and slower orbital speeds. Jupiter, being much farther from the Sun than Earth or Mars,
moves more slowly in its orbit.
5. Which of the following would happen if the Earth started spinning (rotating) in the opposite
direction?
- A. The Sun would rise in the West and set in the East
- B. The Sun would rise in the East and set in the West
- C. Days would become longer
- D. The seasons would reverse
,Correct Answer: A. The Sun would rise in the West and set in the East
Explanation: The direction of sunrise and sunset is determined by Earth's rotation. If Earth rotated
the opposite direction, the Sun would appear to rise in the west and set in the east.
6. Why is it warm in Michigan in the summer?
- A. Earth is closer to the Sun in summer
- B. The tilt of Earth's axis means Michigan receives more direct sunlight
- C. The Sun emits more energy in summer
- D. The ozone layer is thinner in summer
Correct Answer: B. The tilt of Earth's axis means Michigan receives more direct sunlight
Explanation: Earth's axis is tilted about 23.5 degrees. During summer in the Northern Hemisphere,
the North Pole is tilted toward the Sun, causing sunlight to strike more directly and for longer
hours, which warms the region.
7. If the Moon is full at midnight, what will it be at 2 AM the same night?
- A. New moon
- B. First quarter
- C. Full
- D. Waning gibbous
Correct Answer: C. Full
Explanation: A full moon rises at sunset, reaches its highest point (meridian) at midnight, and sets
at sunrise. It remains full throughout the night.
, 8. Why are astronauts weightless in the Space Station?
- A. There is no gravity in space
- B. The Space Station is beyond Earth's gravitational pull
- C. The Space Station is free falling around the Earth
- D. They are too far from the Sun
Correct Answer: C. The Space Station is free falling around the Earth
Explanation: Astronauts experience weightlessness because they are in continuous free fall around
Earth. Gravity is still present (about 90% of surface gravity), but both the station and astronauts
are falling together, creating the sensation of weightlessness.
9. The mass of Jupiter can be calculated by measuring:
- A. Its diameter and density
- B. The orbital period and distance of one of its moons
- C. Its temperature and brightness
- D. Its rotation speed
Correct Answer: B. The orbital period and distance of one of its moons
Explanation: Using Newton's form of Kepler's third law, the mass of a central body can be
calculated from the orbital period and distance of any object orbiting it. This method works for
Jupiter using its moons.
10. Where in an elliptical orbit is a comet moving the fastest?
- A. At its farthest point from the Sun (aphelion)
- B. At its closest point to the Sun (perihelion)
- C. At the midpoint of the orbit
- D. Speed is constant throughout the orbit
Answers & Explanations | Human Biology A+ Study Guide
1. What is the approximate age of the Universe?
- A. 4.5 billion years
- B. 8.7 billion years
- C. 13.8 billion years
- D. 100 billion years
Correct Answer: C. 13.8 billion years
Explanation: The age of the universe has been determined through measurements of the cosmic
microwave background radiation and the expansion rate (Hubble constant). The current scientific
consensus, based on data from the Planck satellite, is that the universe is approximately 13.8 billion
years old.
2. What is the approximate age of the solar system?
- A. 4.5 billion years
- B. 10 billion years
- C. 13.8 billion years
- D. 100 million years
Correct Answer: A. 4.5 billion years
Explanation: Radioactive dating of meteorites and rocks shows that the solar system formed about
4.5–4.6 billion years ago. The sun is also about this age.
,3. What fraction of the solar system's total mass is contained in the Sun?
- A. 50%
- B. 75%
- C. 99.8%
- D. 99.98%
Correct Answer: C. 99.8%
Explanation: The Sun contains about 99.8% of the total mass of the entire solar system. Jupiter
contains most of the remaining 0.2%.
4. Which planet is moving more slowly around the Sun?
- A. Mercury
- B. Earth
- C. Mars
- D. Jupiter
Correct Answer: D. Jupiter
Explanation: According to Kepler's third law, planets farther from the Sun have longer orbital
periods and slower orbital speeds. Jupiter, being much farther from the Sun than Earth or Mars,
moves more slowly in its orbit.
5. Which of the following would happen if the Earth started spinning (rotating) in the opposite
direction?
- A. The Sun would rise in the West and set in the East
- B. The Sun would rise in the East and set in the West
- C. Days would become longer
- D. The seasons would reverse
,Correct Answer: A. The Sun would rise in the West and set in the East
Explanation: The direction of sunrise and sunset is determined by Earth's rotation. If Earth rotated
the opposite direction, the Sun would appear to rise in the west and set in the east.
6. Why is it warm in Michigan in the summer?
- A. Earth is closer to the Sun in summer
- B. The tilt of Earth's axis means Michigan receives more direct sunlight
- C. The Sun emits more energy in summer
- D. The ozone layer is thinner in summer
Correct Answer: B. The tilt of Earth's axis means Michigan receives more direct sunlight
Explanation: Earth's axis is tilted about 23.5 degrees. During summer in the Northern Hemisphere,
the North Pole is tilted toward the Sun, causing sunlight to strike more directly and for longer
hours, which warms the region.
7. If the Moon is full at midnight, what will it be at 2 AM the same night?
- A. New moon
- B. First quarter
- C. Full
- D. Waning gibbous
Correct Answer: C. Full
Explanation: A full moon rises at sunset, reaches its highest point (meridian) at midnight, and sets
at sunrise. It remains full throughout the night.
, 8. Why are astronauts weightless in the Space Station?
- A. There is no gravity in space
- B. The Space Station is beyond Earth's gravitational pull
- C. The Space Station is free falling around the Earth
- D. They are too far from the Sun
Correct Answer: C. The Space Station is free falling around the Earth
Explanation: Astronauts experience weightlessness because they are in continuous free fall around
Earth. Gravity is still present (about 90% of surface gravity), but both the station and astronauts
are falling together, creating the sensation of weightlessness.
9. The mass of Jupiter can be calculated by measuring:
- A. Its diameter and density
- B. The orbital period and distance of one of its moons
- C. Its temperature and brightness
- D. Its rotation speed
Correct Answer: B. The orbital period and distance of one of its moons
Explanation: Using Newton's form of Kepler's third law, the mass of a central body can be
calculated from the orbital period and distance of any object orbiting it. This method works for
Jupiter using its moons.
10. Where in an elliptical orbit is a comet moving the fastest?
- A. At its farthest point from the Sun (aphelion)
- B. At its closest point to the Sun (perihelion)
- C. At the midpoint of the orbit
- D. Speed is constant throughout the orbit
