**the National Highway Traffic Safety Administration
And
**the AAA Foundation for Traffic Safety
Would be the most reliable since they aren't about opinions, or not a blog by a teen.
Though I'm not sure if **the Insurance Institute for Highway Safety. Would be a option I think so. Sorry for my unclear explanation goodluck
Porosity is a cavity-like discontinuity and occurs due to the entrapment of gases in the molten weld pool. These entrapped gases don't get a chance to escape from the molten weld pool and hence cause porosity.
<h3>Which discontinuities are caused during welding?</h3>
Weld discontinuities can be defined as "an interruption of the typical structure of a weld, such as a lack of homogeneity in the mechanical, metallurgical or physical characteristics of the weld." Porosity is considered to be the most critical discontinuity. Weld discontinuities include porosity, incomplete fusion, excessive melt.
To learn more about welding visit the link
brainly.com/question/19997700
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Answer:
A group comparison study
Explanation:
In group comparison study, an experiment compares two groups(the beareaved and nonbeareaved adults in the above study) such as in testing the effects of a treatment where a "comparison group" receives either an alternative treatment or no treatment so that it functions as a source of "counterfactual" causal inference for the purpose of the experiment.
The major breakthrough in the study of dreams came in 1953 when researchers Eugene Aserinsky and Nathaniel Kleitman studied and discovered what happens when a person falls asleep.They found that the body enters into a psycho-physiological state in intervals of 90 minute cycles during sleep. This physiological state consists of heightened brain activity, Rapid Eye Movement (REM), increased breathing, a temporary paralysis of the body and genital engorgement. Through experiments, they confirmed that these physiological observations were the result of the person being in the dream state.
