Answer: Sharp spines and waxy stems
Because if they are submerged in the solvent, they would dissolve! This would prevent them from seperating and not allow you to actually record anything
43 inHg = 43 inHg*2.54cm/in = 109.22cmHg * 10 mm/cm = 1092.2 mmHg
14.7 psi = 760 mmHg
1092.2mmHg * 14.7psi / 760 mmHg = 21.13 psi
Answer: option D. 21.13 psi