Part 2 — Questions 21 to 40
21. Which of these activities results in a chemical change?
Correct Answer: D) Burning pieces of wood
Burning alters chemical composition and creates new substances, unlike physical changes.
22. What is true of meiosis?
Correct Answer: B) It is used to generate sex cells
Meiosis creates four haploid sex cells and introduces genetic variation.
23. In genetics, an organism’s appearance is referred to as its:
Correct Answer: D) Phenotype
Phenotype is the observable traits shaped by genotype and environment.
24. People have 46 chromosomes in each body cell. How many are in their gametes?
Correct Answer: B) 23
Gametes are haploid with half the chromosomes so fertilization restores the full set.
25. Which type of symbiotic relationship takes place when one member benefits while the other is harmed?
Correct Answer: C) Parasitism
In parasitism the parasite benefits while the host is harmed.
26. A symbiotic relationship where one benefits and the other is unaffected is called:
Correct Answer: C) Commensalism
Commensalism benefits one partner while the other neither benefits nor is harmed.
27. Animals that feed exclusively on plants are called:
Correct Answer: A) Primary consumers
Primary consumers eat producers like plants.
28. What is the proper order from the bottom of the food chain to the top?
Correct Answer: C) Primary producer, Primary consumer, Secondary consumer, Tertiary consumer, Quaternary consumer
Food chains start with producers, then move up through consumers by feeding level.
29. Which of the following biological classifications is the largest and most inclusive?
Correct Answer: B) Kingdom
Kingdom is broader than phylum, class, family, genus, and species.
30. Which of the following is the correct order of biological classification from most broad to most narrow?
Correct Answer: B) Domain, Kingdom, Phylum, Class, Order, Family, Genus, Species
This is the modern taxonomic hierarchy.
31. A genus classification contains several:
Correct Answer: A) Species
A genus groups closely related species.
32. What is true of a hydrogen atom that lacks a neutron? Which element does not contain any neutrons?
Correct Answer: D) Hydrogen
The most common hydrogen isotope (protium) has one proton and no neutrons.
33. How many atoms are in a single molecule of water H2O?
Correct Answer: C) 3
H2O has two hydrogen atoms and one oxygen atom for a total of three atoms.
34. In chemistry, to be classified as an organic substance, a compound must contain:
Correct Answer: C) Carbon atoms
Organic chemistry is defined by compounds containing carbon.
35. Which of the following is a renewable resource?
Correct Answer: C) Peanut oil
Peanut oil comes from plant crops that can be regrown; metals and fossil fuels are nonrenewable.
36. Which of the following is a non-renewable resource?
Correct Answer: C) Copper
Copper is a mineral that does not replenish on human timescales.
37. When scientists measure a liquid’s resistance to flow, they are measuring:
Correct Answer: C) Viscosity
Viscosity quantifies how resistant a fluid is to flow.
38. The chemical formula of a compound describes:
Correct Answer: C) The ratio of elements in the compound
A chemical formula shows how many atoms of each element are present in a molecule.
39. The tympanic membranes are also known as the:
Correct Answer: C) Eardrum
The tympanic membrane is the eardrum that transmits sound vibrations.
40. Regeneration in humans is limited to:
Correct Answer: D) Healing of wounds
Humans can repair tissues and heal wounds but cannot fully regrow complex lost structures like limbs.