When chemicals react in a closed container, which must be true? A The mass both before and after the reaction is the same.
B. The mass both before and after the reaction is variable.
C. The same number of compounds is present both before and after the
reaction.

Based on your knowledge of industrialization, which of the following statements best describes what is happening in this photo taken in the us around 1910? a. the children pictured here likely worked a 4 - 6-hour shift after school, five days a week, for minimum wage. b. the children pictured here are working illegally, as child labor was prohibited in the late 1880s. the children pictured here likely worked a 12-hour day, six days a week, for about one dollar a week d. the children pictured here likely earned good wages, were protected from risk of injury, and were likely to have a successful, long-term career in this industry.

In what type of geographic location did humans tend to develop civilizations?

Can you think of any problems that could come from using only 15 years of data to predict trends for the next 100 years? explain your answer. how could you prevent some of these problems?