Trilobite fossils are some of the most fossils due to their ease of fossilization and long period of existence. Trilobite species walked along the ocean floor causing them to easily be covered by sediment. Trilobites existed for over 271 million years, longer than the dinosaurs and humans combined. These characteristics provide humans with a large amount of fossil evidence for trilobites. Which statement below best describes the cause of the arrangement of smooth and spikey trilobite fossils observed in the fossil record above?

How does the study of genetic disorders such as pku biologists understand normal alleles?

Agroup of plant cells was exposed to radiation, which damaged the chloroplasts and caused them to lose function. if the mitochondria were unharmed, what would happen to the overall function of the plant cells? a. the cells would not be able to make food, but would be able to release energy from biomolecules. b. the cells would not be able to replicate dna, but would be able to break down waste. c. the cells would not be able to break down waste, but would be able to replicate dna. d. the cells would not be able to release energy from biomolecules, but would be able to make food.

An uncomfortable feeling in the ears when descending in an airplane is caused by changes in air pressure on the: a. inner ear b. middle ear c. eardrum d. hammer/anvil