I can't continue to the next screen
On some lesson screens, you are required to select multiple answers before you can continue to the next screen. Screens that require you to select multiple answers display "Select all answers that apply" at the top of the screen...
...and "Select multiple answers" above the answer choices.
When presented with a screen that requires you to select multiple answers, review the answer choices and select all of those that fit the criteria. Once all correct answers have been chosen, the "Continue" button will appear and you can move to the next screen.