Which molecule can pass freely through the lipid bilayer?
A) K+
B) Na+
C) O2
D) glucose

what bodys are there orbiting?

the principles and empirical processes of discovery and demonstration considered characteristic of or necessary for scientific investigation, generally involving the observation of phenomena, the formulation of a hypothesis concerning the phenomena, experimentation to test the hypothesis, and development of a conclusion that confirms, rejects, or modifies the hypothesis.

sex cells are usually half's then they find another half and make a fertilize egg