Which gases contribute to the greenhouse effect? A. nitrogen and helium
B. carbon dioxide and methane
C. carbon dioxide and helium
D. nitrogen and methane

What does it mean for a cell membrane to be selectively permable

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.

Explain the source of radioactivity in uranium in earth’s crust by which it produces nuclear radiation