Final answer:
The infinitive stem of the verb 'querer' in the future and conditional tenses is 'querr-'.
Step-by-step explanation:
The infinitive stem of the verb 'querer' in the future tense is 'querr-', and in the conditional tense it is 'querría-'. The future tense is formed by adding the endings '-é', '-ás', '-á', '-emos', '-éis', '-án' to the infinitive stem, while the conditional tense is formed by adding the endings '-ía', '-ías', '-ía', '-íamos', '-íais', '-ían' to the infinitive stem.
For example, 'yo querré' means 'I will want' in the future tense, and 'yo querría' means 'I would want' in the conditional tense.