Migratory birds navigate thousands of miles with extraordinary precision. Using Earth's magnetic field as a guide, _____ can locate specific...

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:

• Migratory birds
  • navigate thousands of miles
    • with extraordinary precision.

Sentence 2:

• Using Earth's magnetic field as a guide,
• _____ [?]
  • can locate specific breeding grounds
    • year after year,
    • even returning to the exact same nesting sites.

Sentence 3:

• Ornithologist Marcus Webb
  • has documented this remarkable consistency
    • across multiple species.

Understanding the Meaning

Let's start reading from the beginning.

The first sentence tells us:

• 'Migratory birds navigate thousands of miles with extraordinary precision.'
  • We're talking about birds that migrate - birds that travel long distances
  • They can navigate (find their way) across thousands of miles
  • And they do this with extraordinary precision (very accurately)
  • Notice that 'migratory birds' is plural - we're talking about these birds as a group

Now the second sentence begins:

• 'Using Earth's magnetic field as a guide'
  • This is telling us HOW the birds navigate
  • They use the Earth's magnetic field like a compass

Now here's where we need to fill in the blank. Let's look at our choices:

• The choices are: she, those, it, they
• These are all pronouns - words that refer back to something already mentioned
• We need a pronoun that refers back to 'migratory birds' from the first sentence

What do we notice?

• 'Migratory birds' is plural (more than one bird)
• So we need a plural pronoun to match

Looking at our options:

• 'she' and 'it' are both singular - they refer to just one thing
• 'those' and 'they' are both plural

But which plural pronoun?

• 'Those' is what we call a demonstrative pronoun - it points to specific things ("those birds over there")
• 'They' is a personal pronoun - it simply refers back to something we've already mentioned
• Since we're just continuing to talk about the migratory birds we already introduced, we need 'they'

So we need they.

Now let's read the rest to see the complete picture:

• 'they can locate specific breeding grounds year after year, even returning to the exact same nesting sites.'
  • The birds can find their specific breeding areas
  • They do this year after year - consistently
  • They even return to the exact same nesting sites

The final sentence adds:

• 'Ornithologist Marcus Webb has documented this remarkable consistency across multiple species.'
  • A bird scientist has recorded evidence of this behavior
  • It happens across multiple species - not just one type of bird

The complete picture: Migratory birds can navigate thousands of miles using Earth's magnetic field, and they can find the same breeding grounds and nesting sites year after year - a pattern documented across many species.

Grammar Concept Applied

Matching Pronouns to What They Refer Back To

When you use a pronoun (a word like "he," "she," "it," "they"), it needs to match what it's referring back to - especially in number (singular vs. plural). This word that the pronoun refers to is called the antecedent in grammar terms.

The Pattern:

1. Identify what the pronoun is referring back to
2. Check if that thing is singular (one) or plural (more than one)
3. Choose a pronoun that matches

Examples:

• Plural antecedent: The students studied hard. → They earned high scores.
  • "students" = plural → "they" = plural ✓

• Singular antecedent: The student studied hard. → She earned a high score.
  • "student" = singular → "she" = singular ✓

• Wrong match: The students studied hard. → She earned high scores.
  • "students" = plural → "she" = singular ✗ (number disagreement)

In this question:

• Antecedent: "Migratory birds" (plural)
• Pronoun needed: "they" (plural)
• This creates proper agreement: Migratory birds... they can locate breeding grounds ✓