Fauna refers to the animals of a specific region, habitat, or geological period.

Habitat (A) refers to the environment where an organism lives, not the animals themselves.

Burrow (B) is a hole or tunnel dug by animals for shelter.

Den (D) is a home or shelter for certain animals, but not a general term for all animals of a region.

Imaginary refers to something that exists only in the mind or in fantasy, not in reality.

Sanguinary (A) means involving bloodshed or murder, not related to fancy.

Empyreal (C) refers to something celestial or heavenly, not imaginary.

Insoluble (D) means something that cannot be dissolved or solved, unrelated to imagination.

Potter is a person who makes pottery, especially earthen pots.

Peddler (A) refers to someone who sells goods, but not necessarily pottery.

Vintner (C) is someone who makes or sells wine.

Sculptor (D) is someone who carves or shapes materials into art, typically not pottery.

Optician is a person who tests eyesight and provides corrective lenses like glasses or spectacles.

Oculist (B) is a general term for a person who treats eye diseases, but not specifically for testing eyesight and selling spectacles.

Ophthalmology (C) is the study and treatment of eye diseases, but not the profession of selling spectacles.

Dermatology (D) is the study of the skin, unrelated to eyesight.

The question asks for the name of the area where a river meets the ocean.

·         An Estuary is the correct term. It is a partially enclosed coastal area where fresh river water mixes with salty ocean water, creating brackish water.

·         A Delta is a landform created by river sediment, often found near an estuary, but it is not the mixing body of water itself.

·         A Lagoon is a shallow body of water separated from the sea by a barrier, and doesn't necessarily involve a major river meeting the ocean.

·         A Fjord is a glaciated valley inlet, distinct from a standard river mouth.

Therefore, Estuary is the precise answer for the stretch of water where rivers approach and mix with the ocean.

The question asks for the best term to describe someone seeking to harm another in return for a past injury, which is the definition of revenge.

·         Vengeance is the closest and most formal synonym for revenge.

·         Retaliation is also similar (returning an injury) but Vengeance more directly captures the seeking and inflicting of punishment in this context.

·         Resentment is a feeling (the motive), and Forgiveness is the opposite of revenge.

Therefore, Vengeance (C) is the most appropriate answer.

  Oculist is a person who treats eye diseases, often used interchangeably with ophthalmologist.

  Ophthalmologist (A) is a medical doctor specializing in eye care, but "oculist" is a more general term.

  Pediatrics (B) is the branch of medicine dealing with children.

  Gerontology (C) is the study of aging, not related to eye diseases.

  Janitor is a person who is responsible for cleaning and maintaining buildings.

  Curator (A) is a person who manages a museum or collection of objects.

  Arbitrator (B) is a neutral party who resolves disputes.

  Plumber (D) is someone who works with pipes and plumbing, not responsible for overall building care.

  Horizon is the apparent line where the earth and sky meet.

  Firmament (A) refers to the sky or heavens, but not the line where earth and sky appear to meet.

  Rainbow (C) is a meteorological phenomenon, not a line.

  Orbit (D) refers to the path of a celestial body, not the line where earth and sky meet.

  Jockey is a person who rides horses in races, often professionally.

  Mediator (B) is a person who resolves conflicts, not a horse rider.

  Bronco (C) refers to a type of horse, especially one that is untrained.

               Equine (D) refers to anything related to horses, but not a person who rides them in races.