The singular form is ombudsman.
The singular form of the demonstrative pronoun 'these' is this.
The singular form of feet is foot.
The singular form of "hypothysis" is "hypothesis."
it is already in its singular form.
The singular form is money.
The singular form of "cuffs" is cuff.
The singular form is hilum.
The singular form in stimulus.
The singular form for the plural noun stories is story.
The singular form for the noun families is family. The singular possessive form is family's.
The form hypothesis is the singular form. The plural form is hypotheses.
The form plumber is the singular form; the plural form is plumbers.