How do tetrads differ from sarcinae? O the tetrad is only observed infryalli and the sarcinae in coccobacilli. O the tetrad only appears during reproduction and the sarcinae during dormancy. O the tetrad forms flattened sets of four and the sarcinae form 3-D packets of eight. O the tetrad forms flattened sets of two and the sarcinae form 3-D packets of six.