Which bathymetric technique differentiates between multiple layers of the ocean bottom?

sounding

seismic reflection

radar altimetry

sonar

it would be a gas formation

you didnt put any of the following

answer is: nuclear fusion produces elements that are heavier than helium.

nuclei combine to form a heavier nucleus, releasing energy.  

for example, fusion of hydrogen atoms at the sun.  

this fusion nuclear reaction is in the inner core of the sun and hydrogen (atomic number 1) is conveted into helium (atomic number 2).  

the inner core is the central region of the sun and all solar energy is produced in the core by nuclear fusion.