In 1974, paleontologists working in Ethiopia discovered fossilized bones _____ a previously unknown hominid species that would later be named...

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

First sentence:

• In 1974,
• paleontologists working in Ethiopia
  • discovered fossilized bones
    • from[?]
    • a previously unknown hominid species
      • that would later be named Australopithecus afarensis.

Second sentence:

• The discovery
  • fundamentally changed
    • scientific understanding of human evolution.

Understanding the Meaning

Let's start reading from the beginning:

• In 1974, paleontologists working in Ethiopia discovered fossilized bones

So we have scientists in Ethiopia who found some fossilized bones.

This is where we have the blank:

• discovered fossilized bones from[?] a previously unknown hominid species

Let's look at the choices:

• We're deciding what punctuation (if any) should come after "from"
• Our options are: a colon, nothing, a comma, or a dash

To see what works here, let's read the rest of the sentence and understand what it's saying!

• from a previously unknown hominid species
  • This tells us the SOURCE or origin of the bones
  • They came from a species that wasn't known before

• that would later be named Australopithecus afarensis
  • This adds information about what this species would eventually be called

The second sentence tells us:

• The discovery fundamentally changed scientific understanding of human evolution
  • This was a really important find!

Now, what do we notice about the structure here?

• "from a previously unknown hominid species" is describing where the bones came from
  • The word "from" is a preposition - it shows the relationship between the bones and their source
  • "a previously unknown hominid species" is what "from" connects to
  • These two parts work together as a unit: the preposition needs its object right after it

• This is essential information that flows naturally as part of the sentence
  • We're not adding extra information or creating a break
  • We're completing the thought: bones from [where/what?] → from a previously unknown species

So we need: no punctuation after "from"

The preposition "from" should flow directly into what it's connecting to without any punctuation breaking them apart.

The correct answer is B.

GRAMMAR CONCEPT APPLIED

Keeping Prepositional Phrases Intact

When you use a preposition (words like "from," "to," "in," "with," "about"), it must connect directly to its object without punctuation in between. These elements form a grammatical unit called a prepositional phrase (in grammar terms), and punctuation shouldn't interrupt this unit.

The pattern:

• Preposition + its object (no punctuation between them)

Examples:

Correct: The letter is from my cousin

• "from" = preposition
• "my cousin" = object
• No punctuation between them

Incorrect: The letter is from, my cousin
Incorrect: The letter is from: my cousin

Correct: She walked to the old library

• "to" = preposition
• "the old library" = object
• No punctuation between them

In our question:

• "discovered fossilized bones from a previously unknown hominid species"
  • "from" = preposition
  • "a previously unknown hominid species" = object
  • These must connect directly without punctuation

Even when the object is long or complex, the preposition still needs to flow directly into it. The prepositional phrase works as a complete unit to show the relationship (in this case, the source or origin of the bones).