What is considered to be the first evidence of differentiation in the cells of an embryo?

Organisms are classified, or grouped into categories, based on similarities in their characteristics and/or evolutionary relationships. the study of how organisms are classified is known as

Astudent reads the following text in a science book: scientific evidence tells us that the cause of earths four seasons is the tilt of earth as it revolves around the sound the student is instructed to illustrate this information in a science book. how will the student illustrate winter in the northern hemisphere? a.earths northern hemisphere will tilt away from the sun. b. earths northern hemisphere will tilt toward the sun. c.earths orbit will be farther away than from the sun d. earths southern hemisphere will tilt away from the sun.

Describe characteristics of a good respitory surface