1.
In 2011 investigations into the chemical nature of diamond concluded _________ a form of pure carbon.
2.
The English colonization of Virginia was devised in 1606 by a group of merchants _________ the Virginia Company of London.
3.
The hourglass, an instrument used _________, usually consists of two bulbs united by a narrow neck.
4.
A master is an electronic apparatus that _________ radio and light waves.
5.
The human skin forms _________ against the action of physical, chemical, and bacterial agents on the deeper tissues.
6.
Medical research at the cellular level, _________ research on the immune system, has been made possible through twentieth-century advances in techniques of genetic research.
7.
Living organisms contain more water _________ substance.
8.
The twentieth century has been a period of enormous growth in mathematical research and in the number of mathematicians and fields _________ them.
9.
Columbia University’s School of Public Health is _________ a handful of schools of public health in the United States.
10.
The United States Department of the interior designated the Brooklyn bridge _________ in 1964.
11.
In jazz music, a riff is a simple melodic figure, _________ and repeated several times.
12.
At its center, the sun has a density of over a hundred times _________ and a temperature of 10 to 20 million degrees centigrade.
13.
The United States Congress appropriates some four million dollars _________ the upkeep of the White House grounds.
14.
The sea horse uses _________ to cling to the seaweed and other plants.
15.
In the years ahead, health professionals will be able to enhance or restore health far better _________ at present.
