Which structure is the initial entry way for air to enter the respiratory system?

What was the land like over 500 million years ago? what was under the sea?

Pls ! in your opinion, what are the limiting factors that might affect the growth or diversity of our ecosystem? respond to this question in claim, evidence, reasoning format. 1. make your claim (i are the limiting factors that might affect the growth or diversity of our 2. follow the claim with 3 pieces of evidence. evidence may be taken from the reading, the videos, previous lessons, or googled answers. site sources, too. 3. use reasoning to explain why you chose your evidence.

Which of the following statements about protists are true? a. they are typically found in moist environments. b. they are all unicellular. c. they have a nucleus. d. they are all multicellular.