B. carbon + oxygen -- carbon dioxide
Explanation:
The best equation that describes a reaction where carbon combines by burning in the presence of oxygen to produce carbon dioxide is:
carbon + oxygen -- carbon dioxide
Every chemical reaction is made up of reactants and products
Reactants are the species on the left hand side of an equation, the products are those on the right hand side.
The reactants combines chemically to give produces.
The kind of reaction depicted above is a synthesis or combination reaction where two species combines to gives a product or more;
C + O₂ → CO₂
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Chemical reaction brainly.com/question/3953793
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To determine which object has the greatest acceleration, you would use the formula:
acceleration = (Final Velocity - Initial Velocity) / Time
Just plug-in values for what you have and see which one has the greatest acceleration. If you're given velocity-time graphs, then the one with the steepest slope would have the greatest acceleration.
Answer:
both are correct .... ....
(a) The efficiency of an engine is defined as the ratio between the work done by the engine and the heat it takes in:

The engine in this problem does a work of

and it takes in

of heat, therefore its efficiency is

(b) The heat taken by the machine is 4000 J; of this amount of heat, only 1100 J are converted into useful work. This means that the rest of the heat is wasted. Therefore, the wasted heat is the difference between the heat in input and the work done by the engine:
Answer: polar ice reflecting the Sun's light back toward space