What is the single greatest environmental cause of human illness?

Which organisms have pharyngeal arches that develop from all three germ layers and go through the same development stages as embryos? 1.bird 2.ladybug 3.starfish 4.snake

Elephants in the savanna regions of africa dig holes in dried up river beds to reach water lying just below the surface. these holes provide drinking water for other animals as well. so, without the elephants, many animals might otherwise die from lack of water during the dry season. the location in which the elephants live is an example of a/n and the role they play in creating water holes is an example of a a) ecosystem; habitat b) community; niche c) habitat; niche d) niche; habitat

Mike wants to negatively charge a small rubber ball. which of these methods would successfully charge the ball? a) heating the ball in boiling water b) running the ball over a strong magnet c) rubbing the ball back and forth on carpet d) dropping the ball from a tall bulding submit hint forces in nature (s8p5.b) conductors and insulators id: 10402 hint electrons must be transferred.