What practice of adoption agencies can make adoption studies problematic for researchers interested in disentangling genetic and environmental contributions to human behavior?
a. open adoption
b. environmental grooming
c. selective placement
d. sealed records

The correct answer is option d. "sealed records".

Explanation:

Some adoption agencies give the option that biologically and adopting parents prevent to find, or even know, each other. This practice is known as "sealed records" and support the biological parents to give their children to adoption and avoid any possible criticism for their decision. However, this practice make adoption studies problematic because the researches would not be able to known the genetic contributions from the biological parents.

the framers of the constitution insisted that federal judges be nominated instead of elected due to their desire to have judges above the shifting whims of the masses.

the hope, whether achieved or not, was that federal judges would only be beholden to the law and that by not having judges be elected, they would be protected if that law dictated an outcome that ran counter to popular opinion.

the menstrual cycle – higher tier. negative feedback mechanisms affect the production of hormones in the menstrual cycle. oestrogen also stimulates the release of lh (luteinising hormone) from the pituitary gland, which in turn controls the production of progesterone.