Why did some native american groups build mounds ?

Which of the following is an example of a domesticated animal?

The provisions of subpart d, of the hhs regulations, additional protections for children involved as subjects in research apply to: all research involving childrenall research that is > minimal riskall research funded by any federal agencyall research funded by hhs

The specific department of health and human services (hhs) regulations that apply to research with children are known as: subpart b: additional protections for children involved as subjects in researchsubpart a: the common rulesubpart d: additional protections for children involved as subjects in researchsubpart c: protections for children in research