Invertebrates:
a) are not a monophyletic group.
b) are animals without a backbone.
c) have more species than vertebrates.
d) all of the above. include arthropods, mollusks, and flatworms, among others.

Sydney drew a flow chart to illustrate the nitrogen cycle.which labels best complete the flow chart? x: producers undergo photosynthesis.y: nitrogen compounds are released into the air.x: nitrogen compounds are released into the air.y: producers undergo photosynthesis.x: free nitrogen is in the atmosphere.y: producers absorb nitrogen compounds through their roots.x: producers absorb nitrogen compounds through their roots.y: free nitrogen is in the atmosphere.

Which best describes how the common cold spreads in the human body? a bacteria burst out of normal cells killing them b viruses replicate inside respiratory cells c bacteria inject dna into normal cells d viruses insert dna into bacteria

Describe your dna model. which part do the straws represent? the pushpins? the paper clips and the black dots you made with the marker?