= Solution
\b[Yes.] The baryons carry the oscillatory <baryon transfer function> inherited from the pre-recombination <photon-baryon fluid>. Their later infall toward cold-dark-matter overdensities suppresses the relative mode and drives $\delta_b/\delta_c\to1$, but gravitational evolution does not remove every scale-dependent acoustic phase. The total <cosmological density power spectrum> therefore contains the small wiggles known as a <baryon acoustic oscillation in the matter power spectrum>.
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