Is popping popcorn a physical or chemical change? how can you tell

Eleni and analisa are driving to ms. a's wedding. eleni is going east at a rate of 50 mph and analisa is driving south at 38 mph. at what is the distance between the cars changing when eleni is 1 mile and analisa is 3/4 mile from the wedding?

Which of the following is an example of negative reinforcement? a.marty knocks over his mother's prize fern so she gives him a time out. b.gwen mows the lawn and her dad takes her out for ice cream. c.tara takes an aspirin, and her headache begins to go away. d. peter comes in late from his lunch and is fired from his job.

The biome pictured above is found in areas such as kenya and south africa. the land is grass-covered with very few trees and gazelles and other grazers are common here. why does this biome have a low population of trees? a) large grazing animals destroy the trees. b) it is a deforested rainforest with poor soil. c) it has high temperatures and low precipitation. d) it has a long rainy season followed by flooding.