Penguins that live in the South Pole must deal with the freezing temperature and cold winds. What type of ecological factor is this?

Which is not a characteristic of the phylum Platyhelminthes (flatworms)?

What is Müllerian mimicry?

General mollusk characteristics include:

Sponges are different from all other animals in that they lack true _____. (Your answer should consist of a single word.)

Your answer should consist of a single word. Lichens are symbiotic associations between algae and ____.

Why are flatworms and roundworms of special significance to humans and other animals?

Consider a community of a small field consisting of small flowering plants and grasses. Within this field several types of insects live that feed off the plants.  There are also small rodents who inhabit the field that feed off the insects and plants. Which of the following is true? 

The arachnids (spiders, scorpions, ticks) are the most successful arthropod group.

Which of the following best describes a coelom?