Intracellular digestion is ___________________________ and is found in  ___________.

This dogfish shark pup was nourished by a yolk sac, but not a placenta in the mother’s body.  Therefore, this species is  

The structure labeled is part of the

These organisms are

Which of the following characteristics do chondrichthyes (sharks, skates and rays) and osteichthyes (bony fish) share?

This organism is an adult tunicate. How can this organism be classified in the Phylum Chordata, given its relatively simple body plan?

In deuterostomes the blastopore becomes the

You collect a deposit feeding worm from the mud at the bottom of an estuary.  In which zone did you collect this organism?

Detritus is

Since 1960, atmospheric carbon dioxide has