PLEASE HELP IM FAILING WILL GIVE BRAINLESS

Which statements explains what the fossil records indicates? check all that apply. a) earth is 4.5 billion years old b) many organisms have become extinct c) mammals have always existed on earth d) mass extinctions have occurred several times on earth e) the amount of water on earth has decreased over time?

Tag ctt ggc at what kind of mutation is this?

Cholera is a bacterial infection of the small intestine. vaccination provides protection against cholera. the cholera vaccine is made up of weakend form of the bacteria that causes cholera. the vaccine will stimulate blank production and elicit an immune response. if the infection occurs again, the bodynwill produce an even greater attack on thre bacteria because of blank.