To make most synthetic elements, scientists use powerful machines called a. semiconductors. b. particle accelerators. c. supernovae. d. nebulas.

Scientists use particle accelerators (b)

Your answer should be B) Particles
Sorry if i'm wrong!
Hope this helps!

This is what i found on google “phytoplankton, tiny organisms that live in the ocean, are autotrophs. some types of bacteria are autotrophs. most autotrophs use a process called photosynthesis to make their food.” i hope this you for what your looking for