Which type of elements tend to form ionic bonds

Which of the following is the earliest era of earth's geologic time scale? cenozoic mesozoic precambrian paleozoic

The ultimate purpose of respiration: a. inhale 02 and exhale co2 b. place oxygen in the lungs c. place oxygen in the blood d. deliver oxygen to every blood cell

Which claim correctly describes how genes can produce a phenotype? one gene is responsible for all traits. each trait is determined by a single gene. one gene can be responsible for many traits. each gene is responsible for exactly one trait.