Ozone is dangerous to human health only when it is found in
a. stratosphere b. troposphere c. mesosphere d. thermosphere

Place the steps tor the formation of the enzyme pepsinogen in correct order

Match the types of competition to their descriptions

Which ideas did your answer contain? check all that apply. no food for organisms no oxygen in the atmosphere no trees or flowering plants no products based on trees or plants (building materials, medicines, fuels, fibers) no fossil fuels