Which is a key detail that supports the main idea that there are general principles that guide sports helmet design?
helmets must protect the face.
helmets must not prevent seeing or hearing.
scientists invent new plastics all the time.
materials used for police can be used in sports.

Helmets must not prevent seeing or hearing.

A general principle is almost like a rule. It is an agreed upon standard for a certain thing. In this case, the general principles or standards are for sports helmets. While it is a good idea in some sports for the helmet to protect the face, like the helmet of a hockey goalie, it is not necessary. In biking, horseback riding, baseball, and many other sports, face protection is not a necessity. However, helmets should not prevent seeing or hearing. They may reduce a person's field of vision or obstruct hearing slightly, but they should not prevent it completely. The other options about the type of plastics and materials are not guiding principles because the statements talk about possibilities not something that is consistent all the time.

malvolio only loves olivia because he thinks if they get married to olivia he will have a noble title, people to serve him, and fine clothes to wear. also he thinks if they get married he will have many expensive things, and he thinks he will be able to order toby around. malvolio only wants to be noble and boss people around he dose not really love olivia. but viola love for duke orsino is real she really loves orsino.

i think he will fail because he tried to get her to love him and she said oh, you are sick of self-love, malvolio. there is no slander in an allowed fool. so i think she knows what malvolio is trying to do. she knows that he only wants to marry her because he wants to be noble and boss people around so that it why i think she said oh, you are sick of self-love, malvolio. there is no slander in an allowed fool because she new he was selfish.

after the moon goes from a full moon it turns into a waning gibbous moon.

here's where my answer came from. i hope this .