Fact 1: The emission of sulfur dioxide causes acid rain. Fact 2: Polluted rain is called acid rain . Given the two facts above, answer the question "What causes pollution in rain?" with the following options: - sulfur dioxide - carbon dioxide - nitrogen - contamination - smog - hydrogen - fossil fuels - flooding
sulfur dioxide

Fact 1: Sediment is formed by weathering. Fact 2: Sand and mud are examples of sediments. Given the two facts above, answer the question "What does weathering do?" with the following options: - protect them - form sand - form plants - It expands - form snow - form fossils - Metling snow - watershred
form sand

Fact 1: Male dogs use pheromones in urine to mark their territory. Fact 2: Pheromones are hormones that are thought to stimulate, through smell, sexual reactions in animals. Given the two facts above, answer the question "What do male dogs use to mark their territory?" with the following options: - smell - H 2 O - love - intuition - gourdin - tongue - sight - fur
smell