Answer:
Community trial type of study.
Explanation:
• Since 1945, fluoride was added to Newburgh's water supply.
• Water supply in Kingston was not fluoridated.
• The two communities were experiencing similar tooth decay condition.
• After 10 years, children from Newburgh experienced less tooth decay compared with their counterparts at Kingston, with no side effect on their health.
Answer:
Explanation:
The step by step solution is in the attached file.
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Answer:
Wayback machine
Explanation:
Wayback Machine
calls a "three dimensional index". Kahle and Gilliat created the machine hoping to archive the entire Internet and provide "universal access to all knowledge
Answer:
Pathline
Explanation:
- The smoke coming out of the chimney on a day with variable winds would most closely relate to a path-line. Consider a smoke particle " grey " color particle that is injected into air at every instant in time and follows a continuous "path" along the flow of the of the fluid.
- A streakline concentrates on fluid particles that have gone through a fixed station or point. At some instant of time the position of all these particles are marked and a line is drawn through them.
- The streakline and pathline can coincide on the conditions of flow to be steady that is the rate of change of flow of the air is continuous and does not change with time in a day i.e the variation in the winds or any discontinuity is removed.