Which is the definition of an embryo?
a) prenatal stage of a human up to 8 weeks of development after fertilization.
b) prenatal stage of a human beyond 8 weeks of development after fertilization.
c) prenatal stage of a human up to 9 months of development after fertilization.

Which of the following elements does soil need in the largest quantities to sustain plant life? a. copper b. iron c. nitrogen d. zinc

Crossing over and independent assortment are important activities that occur during meiosis. what is the significance of these activities

Select all the correct answers. which statements fail to meet the requirements of a scientific claim? a) in the final 100 meters of a 10,000-meter race, an athlete's speed is more strongly related to anaerobic efficiency than to aerobic efficiency. b) flowers that reflect the most ultraviolet light are more likely to attract bees and other pollinators than flowers that reflect less ultraviolet light. c) even though evidence indicates that the solar system's planets follow elliptical paths, copernicus's model involving circular orbits is true. d) the evidence supporting newton's laws of motion was accurate in newton's time, but the universe operates differently today.