The film which you called it is photographic film and it is strip like sheet and it's surface is clrear and transparent plastic which is coated on
two sided one side is with gelatin emulsion consists microscopic small light-sensor which is actually very sensitive in nature silver halides crystals. The size shape and other characters of the crystals gives the sensitivity,contrast of different colors combination ,and resolution of the films.
The number 6.022 × 1023 indicating the number of atoms or molecules in a mole of any substance
In a way, all of the answers could be argued for (for example: in the first option: if the scientists' opinions are understood to be "informed understanding of the causes of events"), but one of the options is the best:
Scientific laws describe specific relationships in nature without offering
an explanation.
The reason why I think this is true is that many laws are phased too short and too concise to provide comprehensive explanations, instead they describe the relationships that must hold.
One of the options is pplain false:
Scientific laws explain why natural events occur. -"Scientific laws were theories that have been tested, proven, and adopted as laws." - since they are not adopted as laws.
Answer: C
Explanation:
In endothermic reactions, enthalpy is positive, and in exothermic reactions, enthalpy is negative, So, if enthalpy is positive, then it is an endothermic reaction, and hence is required for the reaction to occur.