Sexual & Asexual Reproduction — Practice · Grade 7 Science

Chapter: Coordination, Defense & Reproduction

What this practice covers

By the end of Sexual & Asexual Reproduction you should be able to:

8 questions, written answer, multiple choice and numeric, each with a worked explanation.

Vocabulary used: reproduction, asexual reproduction, sexual reproduction, fertilization, zygote.

Problem 1

Does asexual reproduction forbid all variation?
Answer and explanation

No. Mutations and environmental effects can produce differences, even when offspring share much inherited material.

Problem 2

Is fertilization the same event as every later cell division?
Answer and explanation

No. Fertilization combines gametes; later divisions and development produce and organize cells.

Problem 3

Why is egg count not the same as successful adult offspring?
Answer and explanation

Some eggs may not be fertilized or survive development, and later survival and reproduction depend on conditions.

Problem 4

Can a reproductive diagram establish personal family information?
Answer and explanation

No. It describes a general process and should not be used to infer or demand a learner’s private history.

Problem 5

Illustrative organisms: A produces new individuals from parent tissue without gamete fusion; B begins with fusion of two gametes. A later develops one new mutation. Classify the mechanisms, explain how A can vary, and distinguish offspring production from successful reproduction over a life cycle.
Answer and explanation

A represents asexual reproduction and B sexual reproduction. A’s new mutation shows that asexual offspring are not guaranteed identical in every detail. The records describe production mechanisms, but later survival and reproductive success depend on development and conditions. More information is needed to compare outcomes, not merely count starting cells.

Identify no fusion in A and fusion in B.

Connect A’s new mutation with variation.

Consider later survival and reproductive stages.

Response criteria

  • Explain the relevant biological process accurately.
  • Use the supplied evidence and show calculation steps with units where needed.
  • Connect a labeled model or mechanism with the claim.
  • State an assumption, evidence limitation, or useful next observation.

Problem 6

Two sexual offspring share parents but differ in traits. Does that by itself contradict inheritance?
Answer and explanation

No. They can receive different combinations of inherited material and experience different environments. Sexual inheritance is not an exact visual blend.

Response criteria

  • Explain the relevant biological process accurately.
  • Use the supplied evidence and show calculation steps with units where needed.
  • Connect a labeled model or mechanism with the claim.
  • State an assumption, evidence limitation, or useful next observation.

Problem 7

What distinguishes the studied sexual reproduction model?
  1. Gamete fusion
  2. Every offspring is identical
  3. No inherited material
  4. Only one possible environment
Answer and explanation

Gamete fusion

Sexual reproduction involves gamete fusion; later development and conditions also affect outcomes.

Problem 8

A supplied record has 30 fertilized eggs from 50 eggs. What percent was fertilized?
Answer and explanation

60 %

30/50×100=60%; this does not give later survival.

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