Which of the following best describes a change in earth’s atmosphere made by early photosynthetic life?

a.
increased level of oxygen

b.
increased level of carbon dioxide

c.
decreased ability to support life

d.
decreased ability to transmit light

Given that the molar mass of nano3  is 85.00  g/mol, what mass of nano3  is needed to make 4.50  l of a 1.50  m nano3solution? use  .6.75 g18.9 g255 g574 g

In a laboratory experiment, a fermenting aqueous solution of glucose and yeast produces carbon dioxide gas and ethanol. the solution was heated by burning natural gas in a bunsen burner to distill the ethanol that formed in the flask. during the distillation, the ethanol evaporated and then condensed in the receiving flask. the flame of the burner was kept too close to the bottom of the flask and some of the glucose decomposed into a black carbon deposit on the inside of the flask. during this experiment the following changes occurred. which of these changes involved a physical change and not a chemical change? check all that apply. 1-condensation of ethanol 2-evaporation of ethanol 3- formation of carbon dioxide gas from glucose burning of natural gas 4-formation of ethanol from glucose by yeast 5-formation of a carbon deposit inside the flask

The best solution for preventing harm to people and pets from severe hurricanes involves determining and warning residents about what