[ Vocabulary ]
An event, condition, or factor that can be changed or controlled in order to study or test a hypothesis in a scientific experiment.
A. field study
B. trials
C. evidence
D. variable

Random Topics:
Modal Verbs for PossibilityAdverb Of PlaceActive and PassiveModals and AdviceDirect Object and Indirect ObjectModals for ObligationGrammar SuffixesIntermediate PrepositionsIdentifying Sentence TypesPassive Voice - Present ContinuousOther quiz:
Grammar › ViewIf she ___ me, tell her to leave a message.
A. calls
B. will call
C. called
D. would call
Past Participle › View
The ports were reached by the sailors were under the control of a foreign nation.
A. True
B. False
Someone tried to steal her phone while she … for a railway ticket.
- queued
- was queuing
Tenses › View
When Bob went to bed last night, he __________ (brush) his teeth.
A. brushes
B. brush
C. had brushed
D. had brush
