Although they were once classed together, archaea and bacteria have now been separated into two different domains. why was this change necessary?

a. the archaea only have cell membranes and the bacteria only have cell walls.
b. the two groups are composed of species with different cell sizes.
c. the archaea have nuclei and the bacteria do not.
d. the two groups replicate their dna in different ways.

The diagram shows a fossil of an ancient whale skull and a skull of a present-day whale. the ancient whale is extinct and is believed to be an ancestor of the present-day whale. what do these skulls most likely show that supports darwin’s theory of evolution? all populations can adapt and survive. only some organisms have a common ancestor. populations change slowly over time. populations rapidly become extinct.

Here's one way to follow the scientific method. place the missing steps in the correct position in the process.

How much time has elapsed from the very beginning of "the memior of the conquistador bernal diaz del castillo" to the end? a. castillo's whole life b. a quarter of an hour c. a few weeks d. a decade