_____________ are invertebrates with jointed appendages with an external skeleton (exoskeleton).

Which of the following is a characteristics of lake and pond biomes? 

True or False: Acoelomates do not have an internal body cavity. 

________ is a self-sacrificing behavior that decreases an individual’s ability to produce offspring/ fitness but helps other produces more offspring. 

Animals that display ____________ have body parts repeated around a central axis and do not have distinct right and left halves. 

True or False: The influenza virus causes “stomach flu.”  It is not a respiratory infection.  

Which of the following is associated with plants?

__________________ are the two groups of seed producing plants.

True or False: Homologous structures (like the bones in the forearm of humans, whales, and dogs) share the same basic form resulting from their origin in a common ancestor.  

Define altruistic behavior and explain kin selection, reciprocal altruism, and mutualism.