2. Absorption, injection, ingestion, inhalation
Absorption, injection, ingestion and inhalation correctly identifies the four ‘routes of entry’ for toxic substances into the body.
The exposure of chemical can have a potential health effects. But, its effect depends upon a number of factors. Some of the factors include chemical toxicity, exposure dose, route of exposure (routes of chemical entry), time duration, and any further reactions.
The four main routes of entry are inhalation, ingestion, injection, and absorption. (Source)