Answer:
Starting molecules not completely and quickly convert to its possible product because an activation energy barrier exist that must be overcome for conversion to product.
Explanation:
The activation energy of a chemical reaction is closely related to its rate. This is because molecules can only complete the reaction once they have reached the top of the activation energy barrier. The higher the barrier is, the fewer molecules that will have enough energy to make it over at any given moment.
Many reactions have such high activation energies that they basically don't proceed at all without an input of energy. For instance, the combustion of a fuel like propane releases energy, but the rate of reaction is effectively zero at room temperature. Once a spark has provided enough energy to get some molecules over the activation energy barrier, those molecules complete the reaction, releasing energy. The released energy helps other fuel molecules get over the energy barrier as well, leading to a chain reaction.
Cells, tissues, organs, organ systems, whole organism
Ans. (B). Genes.
The chemicals that kill the weeds are known as herbicides. Herbicide-resistance is defined as the inherited ability of weeds to survive an application of herbicide, that can kill a normal weed plant of same species.
The resistance develops due to mutations in genes that were sensitive to those chemicals in wild-type forms. As genes are responsible for transfer of characteristics from one to another generation, the herbicide-resistance is also passed down to generations through genes.
Thus, the correct answer is option (B).
S.c.a. is an inherited blood disease.
