True in most cases unless they erode then the younger ones will be on top
The first one seems the most correct
a volcano is a mountain or hill, typically conical, having a crater or vent through which lava, rock fragments, hot vapor, and gas are being or have been erupted from the earth's crust.
There are three main types of volcano - composite or strato,shield and dome. Composite volcanoes, sometimes known as strato volcanoes, are steep sided cones formed from layers of ash and [lava] flows. The eruptions from these volcanoes may be a pyroclastic flow rather than a flow of lava.
Answer: Codon
Explanation: A codon is a triplet of nucleotides in an mRNA that codes for specific amino acids. There are 64 possible codons. They are called the genetic codes. Three of these codons (UAA, UAG, UGA) do not code any known amino acid and are thus called termination codons. One of the codons (AUG) signals the beginning of translation and is thus called initiation codon.