Answer:
Negative effects: Cutting down trees and littering have a negative effect on animals and plants.
Positive effects: Protecting endangered species and cleaning lakes and seas
Step-by-step explanation:
Ecosystem science is the study of interrelationships among living organisms, biochemical processes, and human activities in ecological communities.
Two human activities which affect the ecosystem negatively:
1. Cutting down trees
2. littering harm animals and plants.
Two human activities which affect the ecosystem positively
1. Protecting endangered species
2. cleaning lakes and seas