On most days, rebecca feels depressed and finds it difficult to get out of bed and go about her daily tasks. about once a month, however, she becomes extremely energized, sociable, and feels extremely happy. this high mood lasts for about a week, and then she goes back to feeling depressed. based on her symptoms, rebecca probably would be diagnosed with:

Rebecca is surely going to be diagnosed with Bipolar disorder which is a mental health condition of emotional high and low mood

Explanation:

Bipolar disorder also known as manic depression it's mainly a mental health condition that results in severe mood swings such as high emotional feelings (mania or hypomania) and low emotional feelings (depression).

would be the second part, plants.

energy (sun) -> producers -> consumers -> decomposers