Which phrase best indicates the passage’s main idea? A recent report revealed that about 70 percent of American silent films are lost. With the arrival of talking films in the 1920s, silent films became unprofitable. So film studios threw away most of them. Some films were saved, but many of them were later lost in fires caused by the nitrate in film reels. Several other films were destroyed when they were recycled for their metal content.

right angles are formed by perpendicular lines. if the lines would extend, to make two intersecting lines, they would form four right angles.

yes yes it does !

martians or other types of aliens represent a unique fear as opposed to zombies. vampires and other types of monsters.   in most sci-fi stories, aliens come from other worlds and have different or more advanced technology.   abductions and experimentation on human bodies that involve these technologies, or the use of these technologies against human beings and the use of unknown "powers", are a type of fear that's different from that of other types of monsters.