Question

read the paragraph.
forests are more than just a pretty addition to the landscape. forests help the environment by soaking up carbon dioxide, conserving soil, and preventing flooding. forests help people by providing a place to live and by providing jobs. over 300 million people worldwide live in forests, and over 1.6 billion people depend on forests for their jobs.
which best revises a sentence from the paragraph by adding an appropriate transition?
similarly, forests are more than just a pretty addition to the landscape.
to summarize, over 300 million people worldwide live in forests, and over 1.6 billion people depend on forests for their jobs.
however, forests help people by providing a place to live and by providing jobs.
for example, forests help the environment by soaking up carbon dioxide, conserving soil, and preventing flooding.

Explanation:

The original sentence "Forests are more than just a pretty addition to the landscape. Forests help the environment by soaking up carbon dioxide, conserving soil, and preventing flooding. Forests help people by providing a place to live and by providing jobs. Over 300 million people worldwide live in forests, and over 1.6 billion people depend on forests for their jobs." The second option "To summarize, over 300 million people worldwide live in forests, and over 1.6 billion people depend on forests for their jobs." adds the transition "To summarize" which is appropriate as it is moving from listing the general benefits (helping environment, providing living place and jobs) to a specific summary about the number of people depending on forests. The other options either don't add a proper transition (first option has no real transition word/phrase that shows a summary aspect), use an incorrect transition (third option "However" is for contrast which isn't the case here as it's a continuation of positive points about forests), or use an example - type transition ("For example") which is wrong as it's a summary not an example.

Answer:

The second option (To summarize, over 300 million people worldwide live in forests, and over 1.6 billion people depend on forests for their jobs.) is the correct answer.