D. precision. At first glance you can mark out A and B because the answers does not relate to the question. If question had said "what do you call it when the measurement is close to the actual answer" then you would have picked C. So that leaves you D. precision.
A) a column
example: earth alkaline metals
Answer A )
Potassium chloride
K+ Cl-
hope this helps!.
Explanation:
I can give you some examples;
1) water
2) biomass
3)Soil
4) forest...
I hope this will help you
Answer : The type of reaction described in the sentence is Synthesis or Combination
Explanation :
The balanced equation for the reaction between Phosphorous and Oxygen gas can be written as

From the above equation we can see that there are two different reactants ( P and O₂ ) which are combining with each other to give a single product.
This type of reaction is known as Combination or Synthesis.
A general form of Synthesis reaction is given below.

Here we can conclude that a synthesis / combination reaction is the one where 2 or more reactants combine together to give only one product .