Elective courses give students a chance to explore subjects not typically valued and explore interests they didn't know they had. This exploration will also let them discover career options they had not even considered a possibility. This helps them expand their horizons and grow as people.
I can't help you with the second one, sorry. the whole writing your highschool plan in middle school is B.S. I changed my direction completely. I started out focusing on welding and car repair and ended up in the radio club and focusing on culinary and baking courses. all you need to know in middle school is a reasonable understanding of the pathways your highschool is providing and what you enjoy.
If there is one class that should be required for high school graduation it should be Home Economics of some sort. No matter what profession a person goes into they should have a grasp on how to take care of themselves. A typical home ec class includes brief rundowns on how to calculate a monthly budget, how to cook a basic meal (so you aren't just surviving on instant ramen), how to write a resume, how to sew a button or mend a garment , and how to manage a social group/ interaction. In my opinion, each of these should be considered the examples of why it should be required because they are necessary whether you are going to be a janitor or a doctor.
Answer:
The development and proliferation of algal blooms likely result from a combination of environmental factors including available nutrients, temperature, sunlight, ecosystem disturbance (stable/mixing conditions, turbidity), hydrology (river flow and water storage levels) and the water chemistry
