Final answer:
In "Silent Spring" by Rachel Carson, the natural world sicken due to the actions of pesticide companies and chemical manufacturers.
Step-by-step explanation:
In the book "Silent Spring" by Rachel Carson, the natural world is shown to sicken due to the actions of c) Pesticide companies and d) Chemical manufacturers. Carson drew attention to the harmful effects of pesticides, such as DDT, on the environment and wildlife. She highlighted how the widespread and indiscriminate use of chemical pesticides was causing ecological dangers and harming animals, including birds and fish. Her work influenced the environmental movement and led to the banning of DDT in the United States.