CSLB General Building (B) — All Questions
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Which part of a plant cell captures light energy for photosynthesis?
- a.Nucleus
- b.Ribosome
- c.Chloroplast✓
- d.Cell wall
Chloroplasts contain chlorophyll, the pigment that absorbs sunlight to power photosynthesis. The nucleus stores genetic material, and ribosomes build proteins. Photosynthesis converts light energy into chemical energy stored in sugars.
What is the chemical formula for water?
- a.CO2
- b.NaCl
- c.O2
- d.H2O✓
Water is made of two hydrogen atoms and one oxygen atom, giving the formula H2O. CO2 is carbon dioxide and NaCl is table salt. Chemical formulas show the types and numbers of atoms in a molecule.
In a food chain, organisms that make their own food using sunlight are called—
- a.producers✓
- b.consumers
- c.decomposers
- d.predators
Producers, such as green plants, make their own food through photosynthesis and form the base of a food chain. Consumers eat other organisms, and decomposers break down dead matter. Energy flows from producers to consumers.
Which gas do humans need to breathe in to survive?
- a.Carbon dioxide
- b.Oxygen✓
- c.Nitrogen
- d.Hydrogen
Humans inhale oxygen, which cells use to release energy from food through respiration. We exhale carbon dioxide as a waste product. Although nitrogen is the most abundant gas in air, the body does not use it for respiration.
A scientist records that a substance boils at 100°C at sea level. Boiling point is an example of a—
- a.chemical change
- b.living factor
- c.physical property✓
- d.chemical formula
Boiling point is a physical property because it can be measured without changing the substance's identity. A chemical change would produce a new substance. Physical properties include color, density, and melting point.
Which of the following best describes the function of the heart?
- a.It filters waste from the blood.
- b.It controls breathing rate.
- c.It produces digestive enzymes.
- d.It pumps blood throughout the body.✓
The heart is a muscular pump that circulates blood, delivering oxygen and nutrients to the body. The kidneys filter waste, and the pancreas produces digestive enzymes. Circulation keeps every cell supplied with what it needs.
What force pulls objects toward the center of the Earth?
- a.Gravity✓
- b.Magnetism
- c.Friction
- d.Electricity
Gravity is the force that attracts objects toward Earth's center, giving them weight. Friction resists motion between surfaces, and magnetism acts on certain metals. Gravity keeps us and objects on the ground.
A trait passed from parents to offspring through genes is called—
- a.an adaptation
- b.an inherited trait✓
- c.a learned behavior
- d.an instinct
Inherited traits, such as eye color, are passed genetically from parents to offspring. Learned behaviors are acquired through experience, not genes. Genes carry the instructions that determine inherited characteristics.
During the water cycle, what process turns liquid water into water vapor?
- a.Condensation
- b.Precipitation
- c.Evaporation✓
- d.Collection
Evaporation is the change of liquid water into vapor, usually driven by heat from the sun. Condensation is the reverse, forming clouds, and precipitation returns water as rain or snow. Evaporation moves water into the atmosphere.
Which of these is a renewable energy source?
- a.Coal
- b.Natural gas
- c.Petroleum
- d.Solar power✓
Solar power comes from sunlight, which is replenished continuously, making it renewable. Coal, natural gas, and petroleum are fossil fuels that take millions of years to form and can be used up. Renewable sources do not run out on a human timescale.
The smallest unit of life capable of carrying out all life processes is the—
- a.cell✓
- b.atom
- c.molecule
- d.organ
The cell is the basic structural and functional unit of all living things. Atoms and molecules are smaller but are not themselves alive. Organs are made of many cells working together.
A study finds that a group of plants given fertilizer grew taller than plants without it. In this experiment, fertilizer is the—
- a.dependent variable
- b.independent variable✓
- c.control group
- d.conclusion
The independent variable is the factor the scientist deliberately changes; here it is the fertilizer. The plant height that responds is the dependent variable. Well-designed experiments change only one variable at a time.
Which planet is closest to the Sun?
- a.Earth
- b.Venus
- c.Mercury✓
- d.Mars
Mercury is the innermost planet, orbiting nearest to the Sun. Venus is second, Earth third, and Mars fourth. Distance from the Sun affects a planet's temperature and orbital period.
When wood burns, it turns to ash and gas. This is an example of a—
- a.physical change
- b.change of state
- c.reversible change
- d.chemical change✓
Burning is a chemical change because new substances, such as ash and gases, form and cannot easily be turned back into wood. Physical changes, like melting, do not create new substances. Chemical changes rearrange atoms into different compounds.
What do we call the variety of living organisms in an ecosystem?
- a.Biodiversity✓
- b.Population
- c.Habitat
- d.Climate
Biodiversity refers to the range of different species living in an area. A population is one species, and a habitat is where organisms live. High biodiversity often makes ecosystems more stable and resilient.
The process by which a species changes over many generations in response to its environment is called—
- a.digestion
- b.evolution✓
- c.circulation
- d.condensation
Evolution is the gradual change in inherited traits of a population over generations, often through natural selection. It explains how species adapt to their environments over long periods. Individuals do not evolve; populations do.
Which type of blood vessel carries blood away from the heart?
- a.Veins
- b.Capillaries
- c.Arteries✓
- d.Nerves
Arteries carry oxygen-rich blood away from the heart to the body. Veins return blood to the heart, and capillaries connect the two, allowing exchange of gases. Nerves are not blood vessels at all.
A graph shows a town's average temperature rising steadily each decade. This trend best supports the idea of—
- a.seasonal change
- b.an eclipse
- c.daily weather
- d.long-term warming✓
A steady rise across decades indicates a long-term climate trend, not short-term weather. Weather changes day to day, while climate describes patterns over many years. Reading trends from graphs is a key science skill.
Which of the following is a chemical property of a substance?
- a.Its ability to rust✓
- b.Its color
- c.Its mass
- d.Its shape
The ability to rust describes how a substance reacts chemically with oxygen, so it is a chemical property. Color, mass, and shape are physical properties observable without changing the substance. Chemical properties involve how matter transforms into new substances.
In the human body, which system is responsible for breaking down food into nutrients?
- a.Respiratory system
- b.Digestive system✓
- c.Nervous system
- d.Skeletal system
The digestive system breaks food down into nutrients the body can absorb and use. The respiratory system handles gas exchange, and the nervous system sends signals. Digestion begins in the mouth and continues through the stomach and intestines.
Which of these best explains why ice floats on water?
- a.Ice is warmer than water.
- b.Ice has more mass than water.
- c.Ice is less dense than liquid water.✓
- d.Ice contains more salt than water.
Water expands as it freezes, so ice is less dense than liquid water and therefore floats. Density is mass per unit volume. This unusual property of water helps aquatic life survive under frozen surfaces.
Bacteria that break down dead plants and animals are known as—
- a.producers
- b.predators
- c.herbivores
- d.decomposers✓
Decomposers, including many bacteria and fungi, break down dead organisms and return nutrients to the soil. This recycling supports new plant growth. Without decomposers, dead matter and nutrients would accumulate unused.
A meteorologist predicts rain based on falling air pressure. Air pressure is measured with a—
- a.barometer✓
- b.thermometer
- c.anemometer
- d.telescope
A barometer measures air pressure, which helps forecast weather changes. A thermometer measures temperature and an anemometer measures wind speed. Falling air pressure often signals approaching storms.
Which statement correctly describes an atom?
- a.It is a living cell.
- b.It is the smallest unit of an element.✓
- c.It is a type of energy.
- d.It is only found in plants.
An atom is the smallest particle of an element that still retains that element's properties. Atoms combine to form molecules and compounds. They are the fundamental building blocks of all matter, living or not.
The energy stored in food is a form of—
- a.kinetic energy
- b.sound energy
- c.chemical energy✓
- d.light energy
Food stores chemical energy in the bonds of its molecules, which the body releases during digestion and respiration. Kinetic energy is energy of motion. Cells convert this chemical energy into usable forms to power life processes.
Which action would most reduce the amount of waste sent to landfills?
- a.Using more disposable items
- b.Buying products with extra packaging
- c.Burning all trash outdoors
- d.Recycling paper, glass, and plastic✓
Recycling reuses materials like paper, glass, and plastic, keeping them out of landfills. The other choices increase waste or pollution. Reducing, reusing, and recycling are key strategies for conserving resources.
A scientist repeats an experiment several times and gets similar results. This repetition mainly helps to—
- a.make the results more reliable✓
- b.prove the hypothesis is a law
- c.change the independent variable
- d.eliminate the need for a control
Repeating an experiment and getting consistent results makes the findings more reliable and trustworthy. Repetition helps rule out chance errors. Reliable, reproducible data is a cornerstone of the scientific method.