Closure of an area to stop people or goods from entering or leaving a place.

Which of the following is not a common characteristic of agricultural villages throughout the world?

An object weighs 40n in air , weighs 20n when submerged jn water and 30n submerged in a liquid of unknown density .what is the density of the liquid?

Awaiver of the requirement for documentation of informed consent may be granted when: the investigator has no convenient place to store signed consent forms separate from the research datathe only record linking the subject and the research is the consent document and the principal risk is a breach of confidentiality.potential subjects might find some of the research questions embarrassing, personal, or intrusivethe subjects are literate in their own language; however, they do not read, write, or speak english