Ecosystem Interactions
A rabbit population increases rapidly in a grassland. What is the MOST likely immediate effect?
A. Grass population increases
B. Predator population decreases
C. Grass population decreases
D. Soil nutrients increase
C. Grass population decreases
What is the main purpose of cellular respiration?
A. Store DNA
B. Make proteins
C. Produce energy (ATP)
D. Break down lipids
C. Produce energy (ATP)
What is the basic unit of heredity?
A. Chromosome
B.Cell
C. Protein
D. Gene
D. Gene
What is the main function of the immune system?
A. Transport oxygen
B. Fight infections
C. Digest food
D. Produce hormones
B. Fight infections
What is the independent variable in an experiment?
A. The factor that is measured
B. The factor that is changed
C. The constant factor
D. The conclusion
B. The factor that is changed
A new predator is introduced into an ecosystem. Which outcome is MOST likely?
A. All species increase
B. Prey population increases
C. Prey population decreases
D. Producers disappear
C. Prey population decreases
Which organelle is responsible for photosynthesis?
A. Chloroplast
B. Mitochondria
C. Nucleus
D. Ribosome
A. Chloroplast
An organism has two different alleles for a trait. This is called:
A. Homozygous
B. Dominant
C. Heterozygous
D. Recessive
C. Heterozygous
Which system is responsible for transporting oxygen and nutrients?
A. Nervous
B. Digestive
C. Circulatory
D. Respiratory
C. Circulatory
A student tests how sunlight affects plant growth by placing plants in different light conditions.
What is the dependent variable?
A. Amount of sunlight
B. Type of plant
C. Plant growth
D. Soil type
C. Plant growth
In a food web, removing a top predator leads to an increase in herbivores. What happens next?
A. Producers increase
B. Producers decrease
C. Decomposers disappear
D. Energy flow stops
B. Producers decrease
If a cell cannot maintain homeostasis, what will MOST likely happen?
A. It divides faster
B. It stops functioning properly
C. It grows larger
D. It produces more energy
B. It stops functioning properly
A recessive trait appears only when:
A. One dominant allele is present
B. Two recessive alleles are present
C. One recessive allele is present
D. No alleles are present
B. Two recessive alleles are present
White blood cells help the body by:
A. Carrying oxygen
B. Producing energy
C. Digesting food
D. Fighting pathogens
D. Fighting pathogens
A student tests how exercise affects heart rate by measuring heart rate before and after running for 10 minutes.
Which part of this investigation is the independent variable?
A. Time spent running
B. Heart rate
C. Type of shoes worn
D. Student’s age
A. Time spent running
Scientists removed wolves from an ecosystem. Over time, deer populations increased and vegetation decreased significantly.What is the BEST explanation for this change?
A. Wolves increase plant growth
B. Deer populations regulate predator populations
C. Predators help control herbivore populations
D. Plants depend directly on wolves for survival
C. Predators help control herbivore populations
A student observes a cell under a microscope after placing it in a salt solution. The cell membrane pulls away from the cell wall. What is the BEST explanation for this observation?
A. Water moved into the cell by active transport
B. Water moved out of the cell by osmosis
C. Salt moved into the cell by diffusion
D. The cell produced more energy
B. Water moved out of the cell by osmosis
What is the MOST likely result of a mutation in DNA?
A. Always harmful
B. Always beneficial
C. No change ever
D. Can be harmful, beneficial, or neutral
D. Can be harmful, beneficial, or neutral
If the lungs fail to function properly, what happens first?
A. Digestion stops
B. Oxygen levels decrease
C. Muscles grow stronger
D. Blood flow increases
B. Oxygen levels decrease
In an experiment, a student forgets to keep the amount of water the same for all plants. Why is this a problem?
A. It changes the dependent variable
B. It increases accuracy
C. It makes the experiment faster
D. It introduces an uncontrolled variable
D. It introduces an uncontrolled variable
An invasive plant species grows rapidly in a grassland ecosystem and outcompetes native plants for sunlight and nutrients. Over time, herbivore populations begin to decline. What is the MOST likely explanation for this change?
A. Herbivores prefer invasive plants as food
B. Native plants decrease, reducing available food for herbivores
C. Invasive plants increase biodiversity in the ecosystem
D. Herbivores are not affected by plant population changes
B. Native plants decrease, reducing available food for herbivores
A cell is exposed to a toxin that prevents ATP production. After several minutes, the cell can no longer move certain ions across its membrane, even though the concentration gradient remains. What is the MOST likely explanation?
A. Diffusion has stopped because ATP is unavailable
B. Facilitated diffusion depends on ATP
C. Osmosis requires ATP to move water
D. Active transport cannot occur without ATP
D. Active transport cannot occur without ATP
In a certain plant species, purple flowers (P) are dominant over white flowers (p). Two heterozygous plants are crossed. What is the MOST likely outcome of this cross?
A. 100% purple flowers
B. 75% purple flowers and 25% white flowers
C. 50% purple flowers and 50% white flowers
D. 25% purple flowers and 75% white flowers
B. 75% purple flowers and 25% white flowers
A patient has a severe infection that spreads quickly through the body. Despite having a functioning immune system, the infection affects multiple organs in a short period of time. Which system is MOST responsible for the rapid spread of the pathogen?
A. Circulatory system
B. Digestive system
C. Skeletal system
D. Muscular system
A. Circulatory system
A scientist repeats an experiment multiple times and gets similar results each time.
What does this MOST strongly indicate?
A. The experiment is biased
B. The data is unreliable
C. The results are reproducible
D. The hypothesis is incorrect
C. The results are reproducible