Pronoun Referents

When most people think of libraries, they think of books. However, there are as many library services as there are types of people who use them.

• libraries

• library services

• people

A camera takes the light rays that bounce off the subjects being photographed and focuses them on a sheet of film for an instant. This light makes chemical changes in the

coating on the film.

• subjects

• camera

• light rays

• sheet film

Word analysis is not always sufficient to give us the precise definition of a word. Thus, we need to combine it with context clues in order to make it easier for us to decide a clear meaning of the word.

• word analysis

• definition

• meaning

A large group of prey may be easier for a predator to find at any given point than a small one, and predator may think twice before taking on such a group.

• group

• prey

• predator

• point

If a predator does decide to challenge a large group, it may merely encounter a confusing mass of moving bodies and possibly may not succeed in its primary goal.

• group

• mass

• predator

• goal

A huge loss of life resulted from the introduction of Old World diseases into the Americas in the early sixteenth century. The inhabitants of the Americas were separated from Asia, Africa, and Europe by rising oceans following the Ice Ages, and, as a result, they were isolated by means of this watery barrier from numerous virulent epidemic diseases.

• the inhabitants

• epidemic diseases

• rising oceans

• the Ice Age

As a result, they were isolated by means of this watery barrier from numerous virulent epidemic diseases that had developed across the ocean, such as measles, smallpox, pneumonia,

and malaria.

• this watery barrier

• a disease-free environment

• the ocean

• virulent epidemic diseases

Pre-Columbian Americans had a relatively disease-free environment but also lacked the antibodies needed to protect them from bacteria and viruses brought to America by European explorers and colonists.

• the antibodies

• pre-Columbian Americans

• bacteria and viruses

• European explorers and colonists

A devastating outbreak of disease that strikes for the first time against a completely unprotected population is known as a virgin soil epidemic. Virgin soil epidemics contributed to an unbelievable decline in the population of native inhabitants of the Americas, one that has been estimated as an 80 percent decrease of the native population in the centuries following the arrival of Europeans in the Americas.

• a virgin soil epidemic

• the population of native inhabitants

• an unbelievable decline

• the arrival of Europeans

Many millions of years after ferns evolved (but long before the Hawaiian Islands were born from the sea), another kind of flora evolved on Earth: the seed-bearing plants. This was a wonderful biological invention. The seed has an outer coating that surrounds the genetic material of the new plant, and inside this covering is a concentrated supply of nutrients. Thus the seed’s chances of survival are greatly enhanced over those of the naked spore.

• the spread of ferns and mosses in Hawaii

• the creation of the Hawaiian Islands

• the evolution of ferns

• the development of plants that produce seeds