Lamarck's theory of evolution is based on the idea of

Step 1: Analyze the question The question asks what Lamarck's theory of evolution is based on. So we need the key idea that Jean-Baptiste Lamarck proposed.

Step 2: Explain the concept Lamarck (1809) proposed two main ideas:

1. Use and disuse: Organs that are used frequently become stronger and better developed, while those not used weaken and may disappear.
2. Inheritance of acquired characteristics: Traits an organism develops during its lifetime are passed on to its offspring.

The classic example is the giraffe. Lamarck said ancestors stretched their necks to reach high leaves, and the longer necks they gained were passed to their young, so over generations giraffes had longer necks.

Step 3: Check each option

• A. Inheritance of acquired traits: This is Lamarck's central idea. ✔
• B. Survival of the fittest: This belongs to Charles Darwin's natural selection.
• C. Struggle for existence: This is also a Darwinian idea (competition for limited resources).
• D. Plenty of offspring produced: This is again Darwin's observation, influenced by Malthus, that organisms overproduce young.

Step 4: Answer The correct option is A.

Exam tip: Link names to ideas:

• Lamarck → Lazy to Learn? No, "L" = "Life-time changes" are inherited (use and disuse, acquired traits).
• Darwin → Dominant survivors (natural selection, survival of the fittest, struggle for existence).

Modern genetics shows that acquired traits (like a bodybuilder's muscles) are not inherited, which is why Lamarck's theory was rejected. But JAMB still tests it often, so remember it!