Out of the following give choices;
a. All DNA strands
contained only the heavy nitrogen isotope.
b. Half of the DNA strands contained only the light nitrogen
isotope.
c. All DNA strands contained both heavy and light nitrogen
isotopes.
d. All DNA strands contained only the lighter nitrogen
isotope.
The answer is b. Meselson–Stahl experiment demonstrated the semi-conservative model of DNA replication.
When DNA is replicated, one strand of the new double
helix strand is the parent's strand while the other is the newly synthesized
one. This made the semiconservative model stand out over the other two, dispersive
and conservative models.
I believe the answer is minerals.
Minerals are inorganic substances that the body cannot manufacture but that act as catalysts, regulating many vital body processes. Nutrients are substances in food that the body needs to function properly to grow, repair, and supply it with energy. These includes, carbohydrates, proteins, lipids, vitamins and minerals.
I would first,find a way on how to fix the earth.Then I would put houses on the lands.
It is called THERAPEUTIC INDEX. Therapeutic index is the comparison of the amount of a particular drug that causes the desired therapeutic effects and the amount that causes toxicity. The index can be low or high. A drug with a low therapeutic index will require only a small increase in dose to produce toxic effects in users.
Aristotle based his classification system off of observations of animals, and used physical characteristics to divide animals into two groups