When they were first discovered in Australia in 1798, duck-billed, beaver-tailed platypuses so defied categorization that one scientist assigned them...

Let's begin by understanding the meaning of this sentence. We'll use our understanding of pause points and segment the sentence as shown - understanding and assimilating the meaning of each segment bit by bit!

Sentence Structure

Sentence 1:

• When they were first discovered in Australia in 1798,
• duck-billed, beaver-tailed platypuses
  • so defied categorization
  • that one scientist assigned them the name Ornithorhynchus paradoxus:
    • 'paradoxical bird-snout.'

Sentence 2:

• The animal,
  • which lays eggs but also nurses (?) young with milk,
  • has since been classified
    • as belonging to the monotremes group.

Understanding the Meaning

The first sentence sets up the context:

• Back in 1798, when platypuses were first discovered in Australia, they were so weird and unusual that they didn't fit into any existing category.
• One scientist even gave them this name: 'paradoxical bird-snout' - because they were that confusing!

Now the second sentence continues:

• 'The animal' - this refers back to the platypus we were just talking about.
  • So we're now discussing one animal (singular).

The sentence tells us more about this animal:

• 'which lays eggs but also nurses ______ young with milk'

Now here's where we need to fill in the blank.

Let's look at our choices:

• They're/It's are contractions (they are/it is)
• Their/Its are possessive forms

In this context, we're talking about whose young?

• The animal's young - the baby platypuses that belong to the animal
• So we need a possessive form to show ownership

Also, we need to match 'the animal':

• 'The animal' is singular (we're talking about one platypus)
• So we need a singular possessive pronoun

So we need its - the singular possessive form that matches 'the animal.'

The sentence continues:

• 'has since been classified as belonging to the monotremes group'
• This tells us that scientists have now figured out where to place the platypus - in a group called monotremes.

What do we notice about the structure here?

• The pronoun needs to refer back to 'the animal' (its antecedent)
• It needs to match in number - 'the animal' is singular, so the pronoun must be singular too
• It needs to show possession - whose young are being nursed

The correct answer is C. its

GRAMMAR CONCEPT APPLIED

Matching Pronouns to What They Refer To

When you use a pronoun, it needs to match the word it's referring to (called the antecedent in grammar terms) in two important ways:

1. Number Agreement - Singular vs. Plural:

• Singular antecedent → singular pronoun
  • "The dog wagged its tail" (dog = singular, so its)
  • "The animal nurses its young" (animal = singular, so its)
• Plural antecedent → plural pronoun
  • "The dogs wagged their tails" (dogs = plural, so their)
  • "Platypuses nurse their young" (platypuses = plural, so their)

2. Choosing the Right Form - Possessive vs. Contraction:

• Possessive (showing ownership): its, their
  • "The bird built its nest"
  • "The children ate their lunch"
• Contraction (shortened verb form): it's = it is, they're = they are
  • "It's raining" (It is raining)
  • "They're happy" (They are happy)

In this question:

• Antecedent: "The animal" (singular)
• Need: possessive form (whose young?)
• Answer: "its" (singular possessive)