Q1. Of the following research topics, which is most likely to be an observational study? a. The relationship between hours of exercise and sleep. b. Students’ feelings about after-school track practice. c. The difference in minutes a day exercising between boys and girls. d. The types of exercise students engage in after school.

Option(d) is correct option

Explanation:

Observational study is type of non-experimental research that gives no control to researcher for modifying variable.The researcher has duty of observing and collecting information for analysis.

According to the question,study based on type of exercise that students are indulged in after the school is observational study.As activities will be observed and information will be gathered accordingly.

Other options are incorrect because observation study is not described through difference in time of exercise between girls and boys, feeling of students towards after school track practice and relation between sleep hours and exercise.Thus, the correct option is option(d)

this null effect is caused by a weak manipulation and ineffective internal validity. in a scientific study, as the one dr. morimoto is trying to perfom, internal validity refers to the confidence placed in the cause-effect relationship and to how well an experiment is done and able to eliminate confounding variables.        

jupiter is mainly composed of hydrogen and helium just like a star. spectral analysis of jupiter has revealed that in addition to hydrogen and helium, the planet is made of water, methane and ammonia. those elements are in trace amounts. the core of the planet is thought to contain some rock and metallic hydrogen. i hope this will give you the answer to your question! : d