Which of the following symbolizes competition among organisms? -/- +/+ +/ø +/-

What came first the elephent or the crocodile

Why was the sample heated in step 5? describe the chemical principles involved in the reasoning behind this step?

Atypical human cell is approximately 12.00 μm in diameter and enclosed by a membrane that is 5.000 nm thick. (a) what is the volume of the cell including the membrane? (b) what is the volume of the cell membrane? (c) what percent of the total volume does its membrane occupy? to simplify the calculations, model the cell as a sphere. enter your answers using four significant figures.