Read each of the following passages and answer the items that follow. Your answers to these items should be based on the passages only.
Recent technological advances in manned and unmanned undersea vehicles, along with breakthroughs in satellite technology and computer equipment, have overcome some of the limitations of divers and diving equipments for scientists doing research on the great oceans of the world. Without a vehicle, divers often became sluggish, and their mental concentration was severely limited. Because undersea pressure
affects their speech organs, communication among divers has always been difficult or impossible. But today, most oceanographers avoid the use of vulnerable human divers, preferring to reduce the risk to human life and make direct observations by means of instruments that are lowered into the ocean, from samples taken from the water, or from photographs made by orbiting satellites. Direct observations of the ocean floor can be made not only by divers but also by deepdiving submarines in the water and even by the technology of sophisticated aerial photography from vantage points above the surface of the water. Some submarines can dive to depths of more than seven miles and cruise at depths of fifteen thousand feet. In addition, radio-equipped buoys can be operated by remote control in order to transmit information back to land-based laboratories via satellite. Particularly important for ocean study are data about water temperature, currents, and weather. Satellite photographs can show the distribution of sea ice, of slicks, and cloud formations over the ocean. Maps created from satellite pictures can represent the temperature and the colour of the ocean’s surface, enabling researchers to study the ocean currents from laboratories on dry land. Furthermore, computers help oceanographers to collect, organize, and analyze data from submarines and satellites. By creating a model of the ocean’s movement and characteristics, scientists can predict the patterns and possible effects of the ocean on the environment.
Recently, many oceanographers have been relying more on satellites and computers than on research ships or even submarine vehicles because they can supply a greater range of information more quickly and more effectively. Some of humankind’s most serious problems, especially those concerning energy and food, may be solved with the help of observations made possible by this new technology.
The word cruise in the given paragraph could best be replaced by