Give the adjective-forming suffix which indicates pertaining to or located in.  Give the suffix which has analgesic, gastric and toxic as examples.

The suffix that forms adjectives indicating "pertaining to" or "located in" is -ic. This suffix is commonly used in the English language to create adjectives from nouns and often denotes a relationship to the root word.

For example:

1. Analgesic - Pertaining to the relief of pain.
2. Gastric - Pertaining to the stomach.
3. Toxic - Pertaining to poison.

Each of these words takes a base noun (analgesia, gastro-, toxin) and modifies it to describe a characteristic of that noun's effect or location. The use of the suffix -ic is prevalent in scientific and medical terminology to convey specific meanings related to various fields.