African-american participation in congress increased most dramatically after passage of which legislation?

fifteenth amendment
voting rights act
nineteenth amendment
twenty-sixth amendment

The belmont principle of beneficence requires that: a. subjects derive individual benefit from study participation.b. potential benefits justify the risks of harm.c. the study makes a significant contribution to generalizable knowledge.d. risks are managed so that they are no > minimal.

Explain the correlation between industrialization and urban areas

Nami conducts an investigation on plants. she places a grow light on a timer to give the plants different amounts of light to see if this would affect their growth. in this investigation, the amount of light is the .