C. is the answer. i know because i had this question not that long ago.
Do you mean; " A blank is a substance that is made by combining two elements?" (I'm not sure if substances is the right term)
If so then the blank is a compound.
Answer:
Addition of a catalyst can speed up a reaction by providing an alternate reaction pathway that has a lower activation energy
Explanation:
A catalyst is an agent that increases the rate of a chemical reaction by providing an alternate pathway for the reaction that requires a lower activation energy. As the requirement for activation energy is less in the presence of a catalyst, there are more reactant particles becoming involved in the chemical reaction and as such there are more products formed per unit time, or there is an increase in the rate of the reaction
Example of catalyst include
1. Addition of potassium permanganate to hydrogen peroxide to aid in the rapid decomposition into water and oxygen
2. Platinum serves as a catalyst in the complete combustion of carbon monoxide into carbon dioxide.
If we know what we are reading, reaction time to the simple reaction task in this project will be less than reaction time to the voluntary action of your quadriceps, however, if we are reading for the first time, reaction time to the simple reaction task in this project will be more than reaction time to the voluntary action of your quadriceps.
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Explanation:</u></h3>
First, we need to know what is the reaction time. Reaction time is the amount of time it takes to respond to a stimulus. Now we will talk about voluntary and involuntary actions.
Voluntary action is an action that is thought of and consciously performed by the person. So we can say the person has full control over the situation. An involuntary action is one which occurs without the conscious choice of an organism. If the involuntary action occurred as a response to some stimulus it will be known as a reflex. If we compare the reaction time of voluntary action of our quadriceps and the simple reaction to the task given in the project, the reaction time could be less only if we have studied about the given question in the given task.
So the lines what we are reading will come to our mind involuntarily, but if we are talking about typing the answer the reaction time would be more as first, we have to form a structured sentence and then type it, so it will take more time.
