How can toxic chemicals enter the human body?

Toxic chemicals can enter the human body through multiple pathways, making the correct answer comprehensive and accurate. Ingestion refers to consuming contaminated food, water, or substances, which allows toxins to enter the digestive system and subsequently the bloodstream. Inhalation involves breathing in harmful chemicals found in environmental pollutants, smoke, or gases, which can directly impact the lungs and other organs. Skin absorption occurs when toxic substances come into direct contact with the skin, allowing those chemicals to penetrate and enter the body's system.

The other options are limited in scope and do not account for the various ways that toxic substances can affect humans. Understanding the multiple routes of exposure is crucial for proper assessment and management of toxic exposures in clinical settings, emphasizing the importance of being aware of all potential entry points for harmful substances.