Make the nouns plural. phenomenon, crisis, stimulus, index, antenna, formula, datum, nucleus, criterion, analysis, apparatus, basis, appendix, tableau, radius, miasma, hypothesis, axis, genus, vertebra.

Phenomena, crises, stimuli, indexes or indices, antennae or antennas, formulas or formulae, data, nuclei, criteria, analyses, apparatus or apparatuses, bases, appendixes or appendices, tableaux, radii or radiuses, miasmas, hypotheses, axes, genera, vertebrae.