Answer:
D
Explanation: An exothermic change is Because it has heat.
Answer: B
. particle size
Explanation:
Let's begin by explaining that a molecular sieve is a device, whose composition allows the absorbtion of molecules that are small enough to pass through its pores, since it is made up of small pores of a precise and uniform size.
Thus, very small molecules manage to pass through the pores of the sieve, while large ones do not.
So, based on this premise, a molecular sieve separates the substances by their size.
Hence, the correct option is B.
Surveys are the data collection tool and research methods. The questionnaire survey tool is used to collect the data based on questions.
<h3>What are questionnaires?</h3>
Questionnaires are the tool used for the research and the data collection for the analysis, investigation, and conclusion. It is one of the data collection tools that comprises questions and prompts.
Questionnaires are the part of surveys that gathers information on the topic of the research and is easy to analyze and cost-effective. It is a valuable tool that collects data from a large number of participants.
Therefore, the correct blank is the <u>questionnaire</u>.
Learn more about the questionnaire here:
brainly.com/question/20335282
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