The plasma membrane, because it's a selective permeable which means it only allows certain things in like sucrose.
Oxygen-16 and Carbon-12 are stableisotopes of elements O and C respectively. Hence, they do not have half-lives. But Carbon-14 andUranium-238 are radioactive isotopes. Among them Carbon-14 has relatively short half-life as about 5730 years while Uranium-238 has a long half-life as about 4.5 billion years.
Answer is. uranium-238
Answer:
A frogs heart has 3 chambers. Two atria and a single ventricle.