Question

The length of a vertebrate's ______ determine its ability to concentrate urine.
a. axons
b. synapses
c. malpighian tubes
d. nephrons

Answer 1

._. my thinking face

Answer 2

its d? thats what i would say:P

Answer 3

okay thanks

Answer 4

It's very easy if you do it by elimination method. Axons and synapses are part of nervous system so they clearly can't be the answer. Now we are left with `Malphigian Tubes` and `Nephrons`. The former is the excretory organ found in insects (which are definately not vertebrates.) and the later is excretory unit found in vertebrates.