Question

grass starts with 30,000 kcal of energy. a cheetah would acquire \boxed{} kcal of energy after it ate a zebra that had consumed the grass.

Explanation:

Step1: Recall energy transfer rule

In a food chain, energy is transferred with about 10% efficiency (10% rule), meaning each trophic level gets ~10% of the previous level's energy.

Step2: Identify trophic levels

Grass (producer) → Zebra (primary consumer) → Cheetah (secondary consumer).

Step3: Calculate energy for Zebra

Zebra gets 10% of Grass's energy: $30000 \times 0.1 = 3000$ kcal.

Step4: Calculate energy for Cheetah

Cheetah gets 10% of Zebra's energy: $3000 \times 0.1 = 300$ kcal.

Answer:

300