Over the past 60 years, the level of carbon dioxide in the atmosphere has been continually increasing. many scientists hypothesize that this increase has led to an imbalance in the carbon cycle and a climatic trend known as global warming.

Which best describes red blood cells? a. they are colorless b. they protect against disease-carrying microorganisms c. they transport oxygen throughout the body d. they aid in blood clotting

Which of the following is true of microbes? a. ninety-nine percent of all microbes are pathogenic.b. gene expression in bacteria is very similar to gene expression in humans, which facilitates the use of bacteria in recombinant biotechnology and gene therapy.c. all bacterial enzymes are harmful to humans and the environment.d. microbes create pollutants and toxins that harm the environment.

Environmental impacts on evolution : mastery test