Carbon dioxide makes up less than 1 percent of Earth's atmosphere, and oxygen makes up
about 20 percent. These percentages are maintained most directly by
A)
respiration and photosynthesis
the ozone shield
C)
synthesis and digestion
D)
energy recycling in ecosystems

Match the digestive enzymes to the macro molecules they to digest. down fats into glycerol and fatty acids down carbohydrates into simple sugars down nucleic acids into nitrogenous bases and simple sugars down proteins into amino acids

What is the name for a substance formed in a chemical reaction

Tara sees a commercial for a brand of pills that promise to boost energy and people perform better in work and school. as people in the commercial talk about how much better they feel when taking the pill, tara notices a message on the bottom of the screen that reads, "this pill is not approved by doctors and has not been tested in controlled experiments." what is the best conclusion that tara should make about the commercial? it is making scientific claims based on subjective observations. it is making scientific claims based on opinions instead of pseudoscientific facts. it is making pseudoscientific claims based on objective observations. it is making pseudoscientific claims based on opinions instead of scientific facts.