BECE Photosynthesis and Ecosystems 3

Question 1

In the carbon cycle, which process returns carbon dioxide to the atmosphere from living organisms?

Accepted Answer

Cellular respiration

Answer

Cellular respiration in all living organisms breaks down glucose, releasing CO₂ back into the atmosphere.

Question 2

What term describes organisms such as bacteria and fungi that break down dead organic matter?

Accepted Answer

Decomposers

Answer

Decomposers break down dead organic material, recycling nutrients back into the soil for use by producers.

Question 3

Which of the following ecosystems stores the most carbon per unit area?

Accepted Answer

Tropical rainforest

Answer

Tropical rainforests have the highest density of plant biomass, making them the largest terrestrial carbon stores per unit area.

Question 4

An ecosystem loses its top predator. What is the most likely immediate effect?

Accepted Answer

Herbivore populations increase unchecked

Answer

Without top predators, herbivore populations grow unchecked, which can lead to overgrazing and ecosystem destabilization.

Question 5

Which nutrient cycle involves both the processes of fixation and denitrification?

Accepted Answer

Nitrogen cycle

Answer

The nitrogen cycle includes nitrogen fixation (N₂ → usable forms) and denitrification (nitrates → N₂ gas).

(BECE) Basic Education Certificate Examination Practice Test