A placenta can be a source of (stem cells).Logical formLearned from4 sentences. A base may pertain-to a (valve stem).Logical formLearned from4 sentences. (Stem cells) can be from human eggs.Logical formLearned from4 sentences. Stems may shrivel.Logical formLearned from4 sentences. Stems may colour purple.Logical formLearned from4 sentences. A bill may allow (stem cell research).Logical formLearned from4 sentences. Eggs may be laid in stems.Logical formLearned from4 sentences. A stem can be wide.Logical formLearned from4 sentences. A stem can be imperative.Logical formLearned from4 sentences. A base may clasp a stem.Logical formLearned from4 sentences. A stem can be with pitchers.Logical formLearned from4 sentences. A stem may pertain-to species.Logical formLearned from4 sentences. Portion may pertain-to a stem.Logical formLearned from4 sentences. (Bone marrow stem cells) may undergo a use.Logical formLearned from4 sentences. A stem can be bulbous.Logical formLearned from4 sentences.