Red tide, also known as "red tide". Red tide is one or more tiny phytoplankton, protozoa, or bacteria in the ocean that suddenly multiply or accumulate suddenly under certain environmental conditions, causing a certain sea area to change color within a period of Natural ecological phenomenon. Red tide is a marine biological disaster. Usually, the color of the water body is red, yellow, green, and brown due to the number and type of red tide organisms. Based on the above definitions, Which of the following are most likely to be red tide phenomena:. ['The water body turned blue many times in the middle reaches of the Yangtze River.', 'The water of Lake Begnas in Pokhara, Nepal has turned red.', 'Frequent redness of water bodies in the Seto Inland Sea and Ariake Sea.', 'Floods in parts of the Mississippi River.']