This worksheet describes the difference between an independent (manipulated) and dependent (responding) variable and then asks students to practice by identifying variables in short sentences.
Instead of answering questions, students are asked to underline the manipulated variable and highlight the responding variable in each sentence. This can also be accomplished if you assign the google doc to remote learners where they can use the document tools for underlining and highlighting. This is the type of assignment I would probably give to students in class to work on together, but am having to make adjustments due to the remote learning model we have adopted for the Covid-19 pandemic.