FTCE Science 3 — Questions and Answers
Question 1: Which best explains why water molecules are attracted to each other?
- Covalent bonding between molecules
- Van der Waals dispersion forces
- Hydrogen bonding due to polar O-H bonds (Correct answer)
- Ionic attraction between hydrogen and oxygen
Correct answer: Hydrogen bonding due to polar O-H bonds
Water molecules form hydrogen bonds because oxygen is highly electronegative, creating partial charges that attract neighboring water molecules.
Question 2: A student notices that the Moon appears to change shape over a month. What actually causes the Moon's phases?
- Earth's shadow falling on the Moon
- The Moon rotating on its axis at different speeds
- Different portions of the Moon's sunlit half visible from Earth (Correct answer)
- Clouds on the Moon blocking sunlight
Correct answer: Different portions of the Moon's sunlit half visible from Earth
Moon phases result from the changing angle between the Sun, Moon, and Earth, which determines how much of the Moon's illuminated side we see.
Question 3: In a food web, which organism occupies the role of a primary producer?
- Hawk
- Rabbit
- Grass (Correct answer)
- Snake
Correct answer: Grass
Primary producers like grass convert solar energy into chemical energy through photosynthesis, forming the base of the food web.
Question 4: A teacher asks students to identify a controlled variable in an experiment testing how light intensity affects plant growth. Which would be a controlled variable?
- The amount of light each plant receives
- The height of the plant after two weeks
- The amount of water given to each plant (Correct answer)
- The type of light bulb used
Correct answer: The amount of water given to each plant
Controlled variables are factors kept constant so they don't affect the results; water amount must be equal for all plants in this experiment.
Question 5: Which process moves water from soil into plant roots against a concentration gradient?
- Active transport
- Osmosis (Correct answer)
- Diffusion
- Facilitated diffusion
Correct answer: Osmosis
Osmosis moves water from an area of high water concentration (wet soil) into root cells with lower water concentration through a semi-permeable membrane.
Question 6: Which best describes the role of decomposers in an ecosystem?
- They convert sunlight into chemical energy
- They break down dead organic matter and return nutrients to the soil (Correct answer)
- They consume primary producers for energy
- They fix atmospheric nitrogen into usable compounds
Correct answer: They break down dead organic matter and return nutrients to the soil
Decomposers like bacteria and fungi break down dead organisms, recycling essential nutrients back into the soil for use by producers.
Question 7: A student measures the wavelength and frequency of two sound waves. Wave A has a higher frequency than Wave B. What can be concluded about their wavelengths?
- Wave A has a longer wavelength
- Wave A has a shorter wavelength (Correct answer)
- Both waves have equal wavelengths
- Wavelength cannot be determined from frequency
Correct answer: Wave A has a shorter wavelength
Since wave speed is constant in a given medium, frequency and wavelength are inversely related; higher frequency means shorter wavelength.
FTCE Science 3
Which best explains why water molecules are attracted to each other?