In the given ecosystem descriptions:
kelp forest:
Abiotic factors: sunlight, wind/water currents, and soil
Biotic factors: algae, sea otters, sea urchins
coral reef:
Abiotic factors: buoyancy, viscosity, salts
Biotic factors: sea grasses, corals, algae
Comparisons:
Kelp forests and coral reefs both contain a large amount of algae. Both ecosystems need a large amount of sunlight for the growth of corals/kelp. Both need to be semi-close shallow, for the sunlight to reach the sand for the kelp/corals to grow.
Contrasts:
Kelp forests need to grow in rich nutrient waters, unlike corals that can thrive in low-nutrient waters. Corals have a rigid carbon skeleton, which kelps are long and flexible algae plants.
What is being described?
a) The concept of ecosystem succession
b) The impact of climate change on marine ecosystems
c) A comparison of coral reef and kelp forest ecosystems
d) The role of abiotic factors in ecosystem development