Which phyla only has bilateral symmetry?

[ikulu]

I am going over the barron's dat book (I know, a lot of mistakes), and I encountered this question:

Which of the following phyla are only bilaterally symmetrical animals found in?

A) Chordata
B) Echinodermata
C) Mollusca
D) Ctenophora
E) Platyhelminths

I remembered from cliff's ap biology chart that both platyhelminths and chordata are bilaterally symmetrical, so I just picked one (Chordata) and moved on.

Later when I checked the answer, it says only the Platyhelminths has primary bilateral symmetry.

Can someone clarify this for me? Thanks!

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[Toadesque]

Strange question because both have bilateral symmetry. Is it possibly trying to say that Chordates could have both radial and bilateral while platys ONLY have bilateral? I don't recall ever reading that anywhere and it doesn't really make sense in my mind

 

[ikulu]

ya, I'm gonna just ignore that question.

Here's another question though:

A solution of KNO3 is known to have a 0.564 molar concentration. To calculate the concentration of this solution in terms of MOLARITY, which of the following must be specified?

a) Density of solution
b) Volume of solution
c) temperature of solution
d) Ksp of KNO3.

I picked B, but the answer says its A, since we were given molality, we will need the density to convert to molarity.

I am puzzled, is molar concentration referring to molality?

 

[Toadesque]

I have always used molarity interchangeably with molar concentration, and I don't recall ever seeing it refer to molality.