Question

1 multiple choice 20 points
what is the main source of energy for most ecosystems? (dok 1)
soil
air
sunlight
water
2 multiple choice 20 points
which of the following best explains how energy flows through an ecosystem? (dok 2)
energy flows in a circle between plants and animals, without loss.
energy does not flow, it stays in the soil so only soil bacteria have access to it.
energy flows from the sun to plants, then to animals, and finally to decomposers. there is a 90% loss at each level.
energy is created by plants and used by animals, which allows for organisms to easily transfer energy back and forth to each other.

Explanation:

For the first question, in most ecosystems, sunlight is the primary energy source as plants use it for photosynthesis. For the second question, energy flow in an ecosystem is unidirectional (sun - plants - animals - decomposers) and there is energy loss (about 90% at each trophic level) as per the 10% law.

Answer:

1. C. Sunlight
2. C. Energy flows from the sun to plants, then to animals, and finally to decomposers. There is a 90% loss at each level.