Answer:
A. Semi Permeable.
Explanation:
Cell membranes are semi permeable.
The answer is b. radon-222. The alpha decay means that it will emit an alpha particle when decays. The alpha particle has two protons and two neutrons. So Radium(88) minus two protons will become Radon(86). And the atomic mass will become 226-4=222.
Answer:
#1 Exposition
#2 Background information
#3 Complication
this is right unless you're speaking of theme plot conflict climax falling action or conclusion
