Multicellular life appeared about 1 billion years ago name the eon that corresponds to this​

b) the inside picture would look at a very high temperature in a very low ph

hey there hope i ,

the answer is heat

the correct answer is option a, that is, syncline.  

a syncline in a structural geology refers to a fold with younger layers nearer to the midpoint of the structure. these are generally a downward fold (synform), known as a synformal syncline.  

the synclines on a geologic map, are identified as an arrangement of rock layers, with the youngest at the center of the fold or hinge and with a reverse alignment of the same layers of rock on the contrary side of the hinge.