Answer:
A population or community research line can be carried out, wherever at a certain point in time, regardless of whether it is a cross-sectional study.
In addition, the people who would be the population to be studied or the object of study might or might not know the cause of the study (blind) while the researcher could be experimentally participatory.
Explanation:
They are prevalence studies, in which the presence of a health condition or state is determined in a well-defined population and in a determined time frame: one day, one week, a particular moment in life, even if it does not temporarily coincide in all the subjects (for example, the blood pressure figures at the time of entering the school or at the beginning of the holidays, the prevalence of diabetes in hospitalized patients on a given day, etc.).
They are like "photographs" of a state of affairs at a given moment. The simultaneous determination of what is understood by exposure and event does not allow defining causality.
Answer:
In a steam engine into a reciprocating piston cylinder assembly a high pressure steam is been admitted.
Explanation:
Steam engine: High-pressure steam is been injected into a piston-cylinder assembly which is reciprocating in nature. some part of its thermal energy gets converted into movement of the piston to work,When the steam starts expanding to lower pressure.
Apparatus which is separate and a condenser at comparatively low temperature and pressure here steam is passed.The expanded steam can then be made to be free, or, for engine efficiency to be maximum, Rotary motion with a crank-crankshaft assembly similar to that used in automobiles gets transferred from that.
Remaining heat has been now used for warming water.
boiler fired with coal, oil, or natural gas by them the steam gets supplied.
. In many areas, more reliable and economical diesel-electric locomotives gets supplanted by the steam locomotives.
The steam engines today generally are regarded as a unique piece as they are not considered as above reasons are explained.
Nevertheless, the creation of the steam engine played a vital role in the Revolution carried out by the industries by creating a society which now is less dependent on the different windmills, the watermills and mostly the animal power.
Answer:
The five steps involved in the process of natural selection are
Variation • Inheritance • Selection • Time • Adaptation
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•Expert•
Brainly Community Contributor
Answer:
hydrogen atom and oxygen atom
