What evidence do scientists have that Earth has been hit by large objects, like asteroids, in the past? Check all that apply. layer of volcanic ash
layer of burned organic matter
change in average global temperature
mass extinctions
earthquake activity

a tetrad is the foursome during meiosis made by two homologous chromosomes that have each already replicated into a pair of sister chromatids.

ionic bonds are two oppositely charged ions that attract. a sodium ion has a 1 positive charge; a chloride ion has a 1 negative charge. sodium and chloride have oppostive charged ions that attract which forms an ionic bond. a chemical bond formed when two atoms share electrons is called

when it is at an intermediate population density