"poop" that's what she said

Which of the following is the major negative aspect of crossover designs for research studies? a. prohibitive cost b. residual effects c-subject drepout d. incomplete randomization e. large sample size required

Can someone me on this math worksheet about finding the given variable for these angles, and whether the triangles are similar. i really need these answers i’m so confused: ( !

Awoman won a 4000-m race with a time of 12.089 min. what was her rate?