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
Magnesium Sulphate Monohydrate
Lasts are used for photosynthesis .
They have a double membrane around them.
The space inside is called the stroma. The space may contain starch grains and lipid bodies.
In the stroma are structures called thylakoids.
The thylakoids are stacked to form structures called grana.
The grana contain the pigment chlorophyll along with some secondary pigments.
The answer to the question is B
Well it happens every six months, one in summer in June and winter December. And if i'm wrong then i understand :) <span />