H Refer to the Figure Shown Here

question 36

Multiple Choice

h Refer to the figure shown here.Which of the following would not have been a selective agent or pressure that could lead to the reduction in hindlimbs through time?

• A) The animal's body size was too heavy to support the weight on land and hindlimbs were no longer useful.
• B) More emphasis was placed on flexing the backbone than on paddling with hindlimbs for swimming.
• C) Appendages cause resistance, or drag, when moving through water.
• D) Before moving into the ocean, smaller legs were advantageous to escaping predators on land.
• E) With the increased size of the tail and its use in swimming, the hindlimbs were not as necessary.

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Definitions:

DEPT-135

A specialized NMR spectroscopy technique used to differentiate between CH, CH2, and CH3 groups in molecules.

Quaternary

Refers to the fourth-order structure in chemistry or the presence of four different groups attached to a central carbon atom.

Proton Spin Decoupled

A technique used in NMR spectroscopy where the interaction between different hydrogen nuclei ("spin coupling") is removed, simplifying the spectrum.

NMR Spectra

The graphical representation obtained from nuclear magnetic resonance spectroscopy, which provides detailed information about the structure of molecules.