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Nearly everyone believes that the primordial abundances are consistent with BBN (e.g. [153], [1], [11], [7], [72], [154]), but there are many lingering questions about the measurements. The reader will readily detect the two attitudes described by Audouze [54]: ``optimistic'', and ``agnostic and perhaps heretical'' in many papers. Each of us tends to adopt differing attitudes for each nucleus and astrophysical processes. This review favors D/H because it is simple and familiar.

Steigman [109] noted that there was ``a hint of an emerging crisis'' because the 4He abundances appeared to be lower than expected using the eta from the other nuclei, but he recommended much more careful study of the uncertainty in BBN predictions, chemical evolution, and observational uncertainties including systematic effects. Hata et al. [155] and Steigman [156] stated that ``there is a conflict'', referring to the differences in eta implied by low D and low Yp values.

Whether or not there is a crisis depends on the confidence assigned to the answers to three questions:

Some combinations of answers are not consistent with SBBN. Recent data make low D/H seem secure in three quasars plus the ISM, hence the issue is whether there are also other places with high primordial D. Low D/H is compatible with high Yp and depleted 7Li , but not with low Yp or undepleted 7Li . High D is compatible with low Yp and undepleted 7Li , but it is incompatible with the three sites which show low D/H and with Galactic chemical evolution. A factor of ten D depletion would be required in all four places. Low Yp is compatible with undepleted 7Li and high D, but is incompatible with the low D.

A good case has been made for high Yp , explanations have been given why earlier results gave lower values, and the uncertainty appears to be larger than quoted. Hence D and Yp are in agreement.

The 7Li observed in stars on the Spite plateau is lower than values consistent with low D. Depletion might provide an explanation, but the amount of depletion and the dominant mechanism are not known. The lack of scatter implies little depletion, less than expected, which [113], [49] conclude is not sufficient to match low D. Bonifacio & Molaro [140] find a higher 7Li , but still below the level required to match low D without depletion.

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