The change in environments that may have occurred at the end of the paleozoic era may have been caused by
a. mass extinctions
c. plate tectonics
b. evolution of the dinosaurs
d. the beginning of an ice age

Anne, an intern in a microbiology lab, was observing the characteristics of various specimens of protists. match each specimen to the category of protist to which it belongs.

Sarah and john are having a discussion on genetic diversity. sarah believes that it happen over a long period of time. john it happens immediately. who is correct? a. sarah is correct because genetic diversity occurs over a long period of time. b. john is correct because genetic diversity occurs immediately. c. both are correct because genetic variation can occur or long period of time. d. neither are correct because genetic diversity occurs over any period of time

This is a situation in which genes are attached to an organism's sex chromosomes; the sex of an organism influences the expression of a gene.