Read the excerpt from "Edward Jenner and the History of Smallpox and Vaccination.” Smallpox was introduced to Europe sometime between the fifth and seventh centuries and was frequently epidemic during the Middle Ages. The disease greatly affected the development of Western civilization. The first stages of the decline of the Roman Empire (AD 108) coincided with a large-scale epidemic: the plague of Antonine, which accounted for the deaths of almost 7 million people. The Arab expansion, the Crusades, and the discovery of the West Indies all contributed to the spread of the disease.

The author most supports his argument that smallpox devastated mankind over the centuries by providing

a historical timeline.
an alternative claim.
details of a historical incident.
interesting, partially related facts.

Biologists recognize five levels of cell organization. the lowest and simplest is the cellular level. organisms here are either unicellular organisms, like protozoa, or colonial organisms. colonial organisms are composed of single-celled individuals that stay together to sustain the life of the whole colony. next on the scale of complexity is the level occupied by tissue. a tissue is a group of similar cells which perform a similar activity. tissues that are organized around a common function together make up an organ, the third level of complexity. the fourth level of organization is the system, formed by a group of organs which together perform a specific bodily process. the fifth and highest level is the organism level, in which body systems work together in a structure capable of independent life. main idea:

Identify the participle or infinitive phrase in the sentence below

What 3 topics are considering for demonstration speech?