Question

multiple-choice question
what do all life on earth share?
a common genetic code
a common habitat
a common ancestor
a common diet

Explanation:

• Option A: All life on Earth uses the same genetic code (DNA/RNA codons correspond to specific amino acids), so this is correct.
• Option B: Life exists in diverse habitats (oceans, deserts, etc.), so no common habitat.
• Option C: According to evolutionary theory, all life shares a common ancestor (last universal common ancestor), so this is correct.
• Option D: Diets vary (herbivores, carnivores, autotrophs), so no common diet.

Since the question is about what all life shares, both A and C are correct. But if we consider the most fundamental shared aspects:

• The genetic code is universal (all organisms use the same codon - amino acid mapping).
• All life is thought to have evolved from a common ancestor.

If we have to pick the most probable (maybe the question expects multiple correct, but if single, A and C are key. But let's analyze each:

A common genetic code: Yes, all known life uses the same genetic code (with minor exceptions, but generally universal).

A common ancestor: Yes, evolutionary biology supports that all life shares a common ancestor.

A common habitat: No, life is in air, water, land, extreme environments.

A common diet: No, plants make food, animals eat different things.

So the correct options are A. A common genetic code and C. A common ancestor.

Answer:

A. A common genetic code, C. A common ancestor