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18 multiple-choice questions and 14 flashcards on Reproduction, Heredity, and Genetics, about 12% of the 7th Grade Science bank. Every one carries a written rationale.
Reproduction, Heredity, and Genetics is one of 5 chapters in CoStudy's 7th Grade Science (Life Science) bank, and it holds 18 of the bank's 150 multiple-choice questions — roughly 12% of the total. That proportion is not arbitrary: chapters follow the certifying body's published exam outline, and the number of questions in each is set by that domain's published weight, so the share of your practice time this chapter takes matches the share of the real exam it accounts for.
Studying by chapter is worth doing once you have a diagnostic score. A single overall percentage tells you whether you are close; it does not tell you which domain is dragging. Working a weak chapter in isolation, and re-testing it in isolation, is the fastest way to move a score that has stalled — and it is why the mock exams in CoStudy report by domain rather than as one number.
10 questions drawn from this chapter, with the full rationale shown — the controlling principle behind the right answer, and why each wrong option tempts and fails.
Photosynthesis produces:
Answer: D — Glucose and oxygen
6CO₂ + 6H₂O + light → C₆H₁₂O₆ + 6O₂. Glucose (food) and oxygen are produced. (A) those are reactants; (B/C) not products of photosynthesis.
In the same Bb × Bb cross, what fraction of offspring are HETEROZYGOUS (Bb)?
Answer: B — 1/2
B) Bb × Bb → 1 BB : 2 Bb : 1 bb → 2/4 = 1/2 are heterozygous. A) bb only; C) 'has at least one B'; D) wrong.
Which is a BIOTIC factor in an ecosystem?
Answer: D — The presence of bacteria
Biotic factors are living components. Bacteria are living organisms. (A/B/C) are abiotic (non-living physical factors).
Which type of reproduction requires only ONE parent?
Answer: D — Asexual reproduction
Asexual reproduction (budding, binary fission, cloning) requires one parent and produces genetically identical offspring. (A/B/C) all require two parents or two sex cells.
Which best describes the relationship between photosynthesis and cellular respiration?
Answer: D — They are complementary: the products of one are the reactants of the other
Photosynthesis produces glucose and O₂ (used in respiration); respiration produces CO₂ and H₂O (used in photosynthesis). (A) they are deeply linked; (C) only respiration produces CO₂; (B) animals only do respiration.
A student writes: 'My trait is determined entirely by my genes.' The MOST accurate correction is:
Answer: B — Traits are influenced by genes AND environment; phenotype = genotype + environmental factors
B) The genes-determine-everything view is a common misconception. A/C) opposite extremes; D) overly narrow.
Identical twins raised in different homes show somewhat different heights. The BEST inference is:
Answer: C — Both genes and environment (nutrition, health) influence height — heritable does not mean 'genes determine everything'
C) Phenotype = genotype + environment. B) is the common 'genes determine everything' misconception; A) is the opposite overreach; D) monozygotic twins are genetically (near) identical. Heritability quantifies variation, not destiny.
Sexual reproduction increases genetic diversity because:
Answer: D — Genes from two parents are recombined in offspring
D) Recombination + independent assortment generate diversity. A) Irrelevant. B) Mutations occur but aren't compulsory. C) Identical copy is asexual.
In MUTUALISM, the relationship results in:
Answer: C — Both organisms benefiting
Mutualism = mutual benefit. Classic examples: bees and flowers (bee gets nectar; flower gets pollination). (A) no symbiosis benefits both while harming; (B) commensalism; (D) parasitism.
Cellular respiration requires which gas?
Answer: C — Oxygen
Aerobic cellular respiration: C₆H₁₂O₆ + 6O₂ → 6CO₂ + 6H₂O + ATP. Oxygen is consumed. (A) CO₂ is a product; (B/D) not used in this process.
4 cards from the 14 in this chapter.
What's a 'recessive' trait?
One that shows only when both alleles are recessive (bb). Hidden when paired with dominant.
What is 'meiosis'?
Cell division that creates sex cells (eggs/sperm). Produces 4 cells with half the chromosomes.
What does 'inherited trait' mean?
A characteristic passed from parents to offspring through genes.
What is 'DNA'?
Deoxyribonucleic acid — the molecule that contains genetic instructions.
These are a sample. The full Reproduction, Heredity, and Genetics chapter runs 32 items with per-chapter progress tracking, on the web and in the iOS app.
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