In context, which is the best version.
One way that scientists do their job is by conducting experiments. The experiments that scientists conduct are like tests that they perform.
ABy conducting experiments, which are like tests
BBy conducting experiments or conduct tests that they perform.
CBy performing tests such as conducting experiments
DBy conducting tests like experiments which they perform
EBy testing experiments, which are like tests that they conduct
One way that scientists do their job is by conducting experiments. The experiments that scientists conduct are like tests that they perform.
ABy conducting experiments, which are like tests
BBy conducting experiments or conduct tests that they perform.
CBy performing tests such as conducting experiments
DBy conducting tests like experiments which they perform
EBy testing experiments, which are like tests that they conduct