Answer:
B. Cross-Sectional
Explanation:
A Cross-sectional study of design is a kind of design of observational study . In the cross-sectional study, an investigator measures or examines the outcome as well as the exposures in any study participants at the same time.
Cross-sectional design research includes using some different category of the people who differ in some variable of interest but they share few other characteristics, like educational background, socioeconomic status and ethnicity.
A Cross-sectional studies are mostly used by experimenters or researchers to study the developmental psychology in humans.
Thus in the context, the researcher using 50 participants to study the developmental changes in their choices to listen to music is a type of cross sectional research design.
Hence the correct option is (B).
Answer:
The telephone
Explanation:
Alexander Graham Bell patened the telephone on February 14, 1876
Answer:
The eruption of volcano
Explanation:
The volcano named Mount Vesuvius was one of the most dangerous volcanoes in the world and it was a stratovolcano which is characterized by the presence of steep slopes, and alternating layers of volcanic ashes and pyroclastic materials.
The city of Pompeii was located near to this volcano and was destructed when it violently erupted in 78 CE. A large number of pyroclastic materials, along with volcanic ashes, volcanic blocks and toxic gases were released from this volcano at the time of eruption, which covered the city making it up to 6 meters of thick ash beds killing numerous people.
Answer:
Wind, currently the most prevalent source of renewable electricity in the United States, grew 14% in 2020 from 2019. Utility-scale solar generation (from projects greater than 1 megawatt) increased 26%, and small-scale solar, such as grid-connected rooftop solar panels, increased 19%:
