In poetry, an iambic foot is made up of an unstressed followed by a stressed syllable, such as "he sings." true false

True.

Explanation:

In poetry, the use of "iambs" as a meter form where the first syllable forms the unstressed part of the rhythm while the next syllable is the stressed part of the rhythm. In the above provided sentence "He sings", "he" is the unstressed syllable while like it is already written in the question, "SINGS" is already capitalized, thereby suggesting it is the stressed syllable. These two stressed and unstressed syllables are the most  important components of the metrical foot used in poetry.  "Iambs" represent the unstressed and stressed syllables in the poem in poetry.

author – information on the internet with a listed author is one indication of a credible site. the fact that the author is willing to stand behind the information presented (and in some cases, include his or her contact information) is a good indication that the information is reliable.

date – the date of any research information is important, including information found on the internet. by including a date, the website allows readers to make decisions about whether that information is recent enough for their purposes.

sources – credible websites, like books and scholarly articles, should cite the source of the information presented.

domain – some domains such as .com, .org, and .net can be purchased and used by any individual. however, the domain .edu is reserved for colleges and universities, while .gov denotes a government website. these two are usually credible sources for information (though occasionally a university will assign a .edu address to each of its students for personal use, in which case use caution when citing). be careful with the domain .org, because .org is usually used by non-profit organizations which may have an agenda of persuasion rather than education.

site design – this can be very subjective, but a well-designed site can be an indication of more reliable information. good design make information more easily accessible.

writing style – poor spelling and grammar are an indication that the site may not be credible. in an effort to make the information presented easy to understand, credible sites watch writing style closely.

the following key ideas correctly express the key sentence.

restate key idea: most people can learn to swim in ten short lessons.

restate key idea: the majority of water-accident victims require mouth-to-mouth breathing.

restate key idea: an empty, tightly closed gallon jug will support a tired swimmer.  

restate key idea: first aid is to prevent accidents as well as assist in rescue.

explanation: the key idea needs to have the same topic as the key sentence (drowning and safety).