What respiratory structures evolved independently in several invertebrate groups as well as in vertebrates?
a. Lungs
b. Gills
c. Air lobes
d. Tracheal systems
e. Spiracles

Which of the following occurs after a natural or unnatural disturbance in an ecosystem

Research question: why are the carrots that grew on the left side of the garden larger than the carrots that grew on the right side of the garden? which hypothesis is based on this research question? a comparison of people with gardens to people without gardens will show who is likely to live longer. b. carrots are thought to be good for your eyesight and should be eaten regularly. c. carrots that are provided lots of sunlight grow to a larger size than carrots grown in the shade. d. eating fresh vegetables every day is a healthy thing to do.

Which statement is true for bacteria a. bacteria have complex internal structures b. all bacteria are spiral in shape c. all bacteria cause disease in animals d. bacteria break down some foods