Question

read the passage. there are several questions about this passage.

along with university of colorado boulder maritime archaeologist bob
hoefleider and british architect chris brandon, examined samples from
several ancient roman ports. they found that there was, in fact, a key
ingredient that made the material uniquely suited to hold up to the
underwater environment.

5

the romans started building with concrete regularly beginning in the
third century b.c., but the earliest uses go back roughly a thousand years
further, to ancient greece. concrete is made of chunks of rubble held together
by mortar. today, mortar is typically made by mixing gravel, sand, and binders
such as lime and cement. according to marie jackson, a research engineer at
the university of california, berkeley, and romacons collaborator, modern
concrete begins to break apart underwater. the material used by the romans
for maritime construction, however, actually gets stronger over time.

6

in the first century b.c., the architect and engineer vitruvius wrote an
expansive work on roman building methods called de architectura. in it, he
describes a substance found near baia, a resort town on the bay of naples,
and around mount vesuvius, that “when mixed with lime and rubble, not only
lends strength to buildings of other kinds, but even when piers of it are
constructed in the sea, they set hard under water.”

7

the romacons team set out to confirm what vitruvius had written by
studying the concrete used to build harbors dotting the mediterranean,
including caesarea, portus (one of rome’s great harbors), pompeiopolis in
modern - day turkey, and heraklion in northern crete. the researchers took
cores, measuring four inches in diameter and up to 20 feet long, from various
parts of each harbor, many of which are now submerged.

8

jackson was then enlisted to investigate the concrete’s physical
characteristics and material makeup. she found that its compressive strength,
meaning the weight it can bear, was much lower than that of modern concrete,
so it wasn’t suitable for tall aboveground architecture. when she compared the

how do the author’s references to ancient writings by
josephus and vitruvius help develop important ideas in
the passage?

1. they show the pride romans felt in the

sophisticated structures that resulted from
roman engineering.

1. they show that modern researchers are part of

a long history of individuals puzzled by roman
engineering.

1. they show the commitment romans had to

future civilizations that might benefit from the
concrete they invented.

1. they show that romans were well aware of the

unique nature of the concrete they used for
underwater construction.

Explanation:

To solve this, we analyze each option:

• Option 1: The references to Josephus and Vitruvius don't focus on Roman pride in structures. Eliminate.
• Option 2: The references are about Roman knowledge of concrete, not modern researchers' puzzlement. Eliminate.
• Option 3: There's no indication the Romans were committed to future civilizations benefiting from their concrete. Eliminate.
• Option 4: Vitruvius described the concrete's underwater strength, and the research confirms it, showing Romans knew the unique nature of their underwater concrete. This matches.

Answer:

1. They show that Romans were well aware of the unique nature of the concrete they used for underwater construction.