Answer: 1. Sea urchins and sea otters
2. They are prey for carnivores.
3. Sea otters, star fish
Explanation:
Sea urchins and sea otters are carnivores as they eat on the flesh of starfish and sea urchins respectively.
Starfish feed on the kelp forests which are the producers in the food chain and the starfish is the primary consumer and prey for sea urchins. So, starfish and kelp forests are the prey in the marine ecosystem.
Keystone species is the one which controls the population of other inferior species in an ecosystem. Here, sea otters consume sea urchins so the population of sea urchins remained in control Starfish controls the population of kelp forest.
The liver primarily uses fatty acid oxidation for energy. Muscle cells use fatty acids, glucose, and amino acids as energy sources. Most cells use glucose for ATP synthesis, but there are other fuel molecules equally important for maintaining the body's equilibrium or homeostasis.
The most prominent role played by plants and algae is that in energy transfer; they are producers and they introduce energy into the ecosystem and different food chains. The earth's only source of energy is the sun, and plants and algae transform this light energy into chemical energy, which is obtained by organisms that consume these plants and algae.
Moreover, plant and algae species are diverse and adapted to carry out their function and survive in different environments, which means they also increase the biodiversity of a region.
A, they use the same bases but in a different order
hope this helped!