Which of the following is a characteristic of all chordates?
A) They all have vertebral columns.
B) They all exhibit radial symmetry.
C) They all have a notochord sometime during their life cycle.
D) They all have an exoskeleton sometime during their life cycle.
C
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Cells regulate their internal osmotic pressure by controlling the solute concentration inside of the cell
A. true B. false
Select the potential problems with using current dispersal barriers (for example, a mountain range) to delineate biogeographical regions. Check all that apply.
_____ A barrier for one group of organisms may not be a barrier for another group of organisms. _____ The world's biota correspond more closely to political boundaries. _____ Global climate change may change the distribution of taxa and the size and/or location of some of the dispersal barriers. _____ Human conflicts lead to ever-changing political boundaries. _____ Distantly related organisms with similar appearance and habits may exist on either side of a dispersal barrier.
Which structure contains the angiosperm egg?
A. Anther B. Stigma C. Embryo sac D. Endosperm E. Style
A collection of similarly specialized cells and any extracellular material they secrete and maintain describes
(a) an organ. (b) a system. (c) a tissue. (d) organelles.