In the final line of this passage, we read: "Animal _____ imply baseness and vulgarity." Select the option that best completes the sentence to show that certain animal related expressions carry such negative suggestions.

Introduction / Context:
This question completes the criticism developed in the passage about how English uses animal related terms. The author wants to say that certain common expressions involving the word animal suggest base or vulgar behaviour. The blank must be filled with a word that normally collocates with animal and whose combination with imply baseness and vulgarity sounds natural and precise in English.

Given Data / Assumptions:

• Sentence: Animal _____ imply baseness and vulgarity.
• Options: breeding, gestures, instincts, species.
• The passage has already discussed how the word "animal" can connote the brutish and the sensual.
• The phrase Animal instincts is a familiar collocation in English.

Concept / Approach:
While several nouns can follow animal, the task is to identify the one that is typically associated with low or uncontrolled behaviour in English usage. The expression animal instincts commonly refers to basic drives like aggression or sexuality, which many people think of as crude or primitive. Saying that animal instincts imply baseness and vulgarity fits both the language of morality and the earlier remarks about brutish and sensual associations. Breeding, gestures and species do not carry the same strong moral judgement when combined with animal in this context.

Step-by-Step Solution:
Step 1: Focus on the phrase imply baseness and vulgarity. The blank should be filled by something that naturally suggests low, uncontrolled drives. Step 2: Consider instincts. Animal instincts is a well known phrase referring to primitive and powerful drives, sometimes contrasted with rational thought. Step 3: Consider breeding. Animal breeding is a technical term in agriculture or zoology related to reproduction and selection, not to moral qualities like baseness or vulgarity. Step 4: Consider gestures. Animal gestures would refer to physical movements, but these do not usually imply vulgarity as a fixed phrase in English. Step 5: Consider species. Animal species is a neutral scientific expression and does not by itself suggest low behaviour. Step 6: Therefore instincts is the only option that naturally combines with animal and supports the claim that such language suggests base qualities.

Verification / Alternative check:
Insert each option into the sentence mentally. Animal instincts imply baseness and vulgarity sounds like a comment on how the phrase animal instincts is interpreted in everyday speech. Animal breeding imply baseness and vulgarity is grammatically rough and conceptually off, as breeding is a neutral activity. Animal gestures and animal species also sound neutral when followed by imply baseness and vulgarity, which shows that they do not carry the implied negative meanings that the author is criticising.

Why Other Options Are Wrong:
Breeding in the phrase good breeding can even be positive when used of humans, and animal breeding is used technically without negative moral overtones; it is not a set phrase linked with vulgarity.
Gestures refers to physical movements or signs, and while some gestures can be rude, animal gestures as a general expression does not carry a fixed association with baseness.

Common Pitfalls:
Some candidates might overthink species because of phrases like human species, but animal species merely categorises animals and does not connect to moral judgement. The exam setter expects you to recognise known collocations rather than invent unusual interpretations. Remember that language criticism often focuses on fixed phrases such as animal instincts, animal cunning or animal passion, so spotting those fixed expressions is a strong clue in these vocabulary based blanks.

Final Answer:
The correct completion is instincts, so the sentence reads: Animal instincts imply baseness and vulgarity.