What is directly responsible for providing energy to phytoplankton in the ocean?

Phytoplankton receive energy through photosynthesis. Photosynthesis is the process of making glucose using sunlight. Carbon dioxide, sunlight, and water combine, producing glucose sugars that the being can use for energy. . Zooplankton however feed off phytoplankton and decaying matter. They are known as detrivores. . Phytoplankton use photosynthesis to make food; zooplankton get energy from other phytoplankton and decay matter.

This is what i did 45-5=4040÷4=10so there are 10 white marbles but am not sure is just a question that am not sure