A form with several small controls may look straightforward, but the control type can change what an answer means. Checkboxes commonly allow independent choices. Radio buttons in the same group represent alternatives, so selecting one changes the selection within that group.
The distinction is documented in MDN’s references for checkboxes and radio buttons. Labels and instructions still matter: a real form may apply additional rules.
For an invented workshop form, “Topics that interest you” could allow writing, audio, and photography together. “Choose one attendance time” would usually require a single option. If your second click removes the first selection, check whether the question is asking for one alternative.
Before submitting
Read the group heading as well as each label. “None of these” can conflict with other selections in a poorly designed checkbox list. If the instructions are ambiguous, ask the organiser instead of assuming the combination will be interpreted correctly.
Use the form’s review screen where available. An unchecked box is not automatically the same as an explicit answer of “No” in every system; the meaning depends on how the application processes it.
For anyone designing a form, make the instruction visible: “Select all that apply” or “Choose one.” Matching the control to the question reduces the amount of interpretation the visitor has to do.