Asubstance that enters earth's cycles and does harm to living things is
a. a pollutant.
b. freshwater.
c. hydrogen.
d. oxygen.

Which sequence represents a cross section of the bilayera hydrophilic head, hydrophobic tail, hydrophobic tail, hydrophilic headb hydrophobic tail, hydrophilic head, hydrophobic tail, hydrophilic headc hydrophobic head, hydrophilic tail. hydrophilic tail, hydrophobic headd hydrophilic tail, hydrophobic head, hydrophobic head, hydrophilic tail

Explain how the political influence of african americans leaders became weaker.

Which statement correctly identifies the scientific question and describes why the question is scientific? question 1 refers to the supernatural.question 2 reflects a moral or social value.question 3 refers to something that can be measured.question 4 reflects a question that can’t be observed.