According to the fossil record, when did the dinosaurs become extinct?
a
at the start of the mesozoic era
b
at the start of the paleozoic era
c
at the end of the mesozoic era
d
at the end of the paleozoic era

Agene with the original sequence of atgtt—tact underwent substitution mutation to form atatt—tact after a few generations. tact is a part of a muscle protein encoding region, and atgtt codes for a digestive enzyme. what will be the effect of this mutation? a. the production of muscle protein will be affected. b. the production of digestive enzymes will be affected. c. the production of both the protein and the enzyme will be affected. d. the production of neither the protein nor the enzyme will be affected.

Tara sees a commercial for a brand of pills that promise to boost energy and people perform better in work and school. as people in the commercial talk about how much better they feel when taking the pill, tara notices a message on the bottom of the screen that reads, "this pill is not approved by doctors and has not been tested in controlled experiments." what is the best conclusion that tara should make about the commercial? it is making scientific claims based on subjective observations. it is making scientific claims based on opinions instead of pseudoscientific facts. it is making pseudoscientific claims based on objective observations. it is making pseudoscientific claims based on opinions instead of scientific facts.

What type of organism is a one-celled organism that functions as a single unit? a. bi-celled b. single-celled c. pre-celled d. multi-celled