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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The incoming and outgoing energy at the Earth’s surface must balance. Or in other words, the flow of energy into the atmosphere must be balanced by an equal flow of energy out of the atmosphere and back to space.<span>
Earth's Energy balance describes how the incoming energy from the sun is used and returned to space. All </span>of the energy entering earth’s atmosphere comes from the sun. Half of it is absorbed by the earth’s surface i.e. the land and oceans, 30% is directly reflected back to space by clouds and 20% is absorbed by the atmosphere and clouds.<span>Earth's </span>actual<span> average global temperature is around 14° C (57 F).</span>
The number of hours required : 37.2 hours
<h3>Further explanation</h3>
Given
⁴²K (potassium -42)
Required
The number of hours
Solution
The atomic nucleus can experience decay into 2 particles or more due to the instability of its atomic nucleus.
Usually, radioactive elements have an unstable atomic nucleus.
Based on Table N(attached), the half-life for ⁴²K is 12.4 hours, which means half of a sample of ⁴²K will decay in 12.4 hours
For three half-life periods :

Answer:
Explanation:
The physical methods of separating mixtures are used in sorting a mixture of substances.
It requires no chemical changes occurring between their components and parts in any significant way.
Examples are:
- Decantation
- Filtration
- Sublimation
- Magnetism
- Centrifugation
The methods simply relies on the physical properties of matter.