In 1900, there were approximately 1.75 billion humans on earth; in 1950, there were approximately 2.3 billion; in the year 2025, approximately 8 billion people will inhabit the biosphere. in the period between 1900 and 2025, what has happened to the human population?

Structures in cells that carry out specific functions.

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.

Out of the seven main animal groups (fish, mammals, birds, insects, reptiles, amphibians, and arachnids), how many contain members with internal backbones? a. 5 b. 3 c. 7 d. 1