Wildlife biologists have been studying the foraging behaviors of migratory hummingbirds in Central America. Their research reveals that the number...

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

• Wildlife biologists have been studying the foraging behaviors
• of migratory hummingbirds
• in Central America.

• Their research reveals
• that the number of [?] spend feeding each day
• increases significantly
• during the pre-migration period
• to build necessary fat reserves.

Understanding the Meaning

Let's start reading:

Wildlife biologists have been studying the foraging behaviors of migratory hummingbirds in Central America.

• So we're learning about research on hummingbirds and how they find food.

Now the sentence continues:
Their research reveals that the number of _____ spend feeding each day increases significantly during the pre-migration period to build necessary fat reserves.

This is where we have the blank. Let's look at the choices:

• A) hour's birds
• B) hours birds
• C) hour's bird's
• D) hours bird's

The choices are asking us to decide:

• Whether we need apostrophes (possessives) or not
• Whether we need singular or plural forms

To see what works here, let's read and really understand the structure of this part!

The sentence is saying: "the number of _____ spend feeding each day increases"

Let's break down what this structure means:

• 'The number... increases'
  • This is the main point - some NUMBER is going up
• 'Of _____ spend feeding each day'
  • This tells us WHAT number we're talking about
  • It's describing the number of something

Now let's understand what this is actually measuring:

• The phrase works like: "the number of hours [that] birds spend feeding"
  • We're counting HOURS (how many hours?)
  • The birds SPEND these hours feeding
  • There's an implied 'that' connecting these ideas
• Think of it like asking: "How many hours do birds spend feeding?"
  • The answer might be "5 hours" or "10 hours"
  • We're counting multiple hours - so HOURS (plural)
  • The birds are doing the spending - so BIRDS (plural, subject of 'spend')

What do we notice about apostrophes here?

• Neither word shows possession (ownership)
  • We're not talking about something belonging to an hour
  • We're not talking about something belonging to a bird
  • We're just counting hours and identifying who spends them
• Both words are simply plurals - no apostrophes needed
  • HOURS = multiple hours (plural noun)
  • BIRDS = the birds doing the action (plural noun, subject of 'spend')

So we need: hours birds

The complete meaning is: The research reveals that the NUMBER of hours birds spend feeding each day goes up significantly before migration - this helps them build up fat reserves for their long journey.

GRAMMAR CONCEPT APPLIED

Possessives vs. Plurals: When to Use Apostrophes

Apostrophes are used to show possession (ownership), not to make plurals. This is a common point of confusion, but the distinction is important:

Plurals (NO apostrophe) - showing multiple items:

• The birds migrate south = multiple birds (plural)
• They spend many hours flying = multiple hours (plural)
• The researchers study them = multiple researchers (plural)

Possessives (WITH apostrophe) - showing ownership:

• The bird's wings = the wings belonging to one bird (possessive singular)
• The hour's duration = the duration of that hour (possessive singular)
• The researcher's findings = the findings belonging to one researcher (possessive singular)

In this question:

• "The number of hours birds spend feeding"
  • HOURS = plural noun (we're counting multiple hours) ✓
  • BIRDS = plural noun (the subject performing the action "spend") ✓
  • Neither shows ownership, so no apostrophes needed
• The structure is: "hours [that] birds spend"
  • Like saying: "How many hours do birds spend feeding?"
  • Answer: "They spend 6 hours" (plural, no possession)

Quick test: Ask yourself "Is something owning/possessing something else?"

• If YES → use apostrophe (possessive)
• If NO, and you just mean "more than one" → no apostrophe (plural)