- Algae are often restricted to the top 100 meters of the ocean
- If an organism is restricted to an area then that organism can only live in that area
- So, algae often can only live in the top 100 meters of the ocean

- Algae often can only live in the top 100 meters of the ocean
- Sunlight can be found in the top 100 meters of the ocean
- So, algae an sunlight often can only be found in the top 100 meters of the ocean

- Solar energy is a kind of light
- Sunlight is a kind of light
- So, sunlight is a kind of solar energy

- Sunlight is a kind of solar energy
- Photosynthesis means producers / green plants convert from carbon dioxide and water and solar energy into carbohydrates and food and oxygen for themselves
- Therefore, a plant requires sunlight for photosynthesis

- A plant requires sunlight for photosynthesis
- Algae is a kind of plant
- So, algae requires sunlight for photosynthesis

- Algae an sunlight often can only be found in the top 100 meters of the ocean
- Algae requires sunlight for photosynthesis
- Hence, algae often can only be found in the top 100 meters of the ocean because they require sunlight

Therefore, algae often can only be found in the top 100 meters of the ocean because they require sunlight
Question
Which BEST explains why green marine algae are most often restricted to the top 100 meters of the ocean?

Context
- Sunlight can be found in the top 100 meters of the ocean 
- Algae are often restricted to the top 100 meters of the ocean 
- Solar energy is a kind of light 
- Algae is a kind of plant 
- If an organism is restricted to an area then that organism can only live in that area 
- Photosynthesis means producers / green plants convert from carbon dioxide and water and solar energy into carbohydrates and food and oxygen for themselves 
- Sunlight is a kind of light