A scratch application consists of just one sprite, which is the crab sprite shown belowWhen the space key is pressed, the crab begins to change depending on the position of the mouse pointer.When the mouse pointer is positioned below the crab, the crab rotates in an anti-clockwise direction with its claws closed. Once the crab faces downward, it stops rotating and its claws become bigger and open.When the mouse pointer is positioned above the crab, the crab rotates in a clockwise direction with its claws closed. Once the crab faces upward, it stops rotating and its claws become bigger and open. Watch the short video to see how the program is meant to behave. Video Player is loading.Play VideoPlayMuteCurrent Time 0:00/Duration 0:41Loaded: 100.00%0:00Stream Type LIVESeek to live, currently behind liveLIVERemaining Time -0:41 1xPlayback Rate2x 1.75x 1.5x 1.25x 1x, selected 0.75x 0.5x ChaptersChapters Descriptionsdescriptions off, selected Captionscaptions settings, opens captions settings dialog captions off, selected Audio TrackPicture-in-PictureFullscreenThis is a modal window.Beginning of dialog window. Escape will cancel and close the window.TextColor[select: White, Black, Red, Green, Blue, Yellow, Magenta, Cyan]Transparency[select: Opaque, Semi-Transparent]BackgroundColor[select: Black, White, Red, Green, Blue, Yellow, Magenta, Cyan]Transparency[select: Opaque, Semi-Transparent, Transparent]WindowColor[select: Black, White, Red, Green, Blue, Yellow, Magenta, Cyan]Transparency[select: Transparent, Semi-Transparent, Opaque]Font Size[select: 50%, 75%, 100%, 125%, 150%, 175%, 200%, 300%, 400%]Text Edge Style[select: None, Raised, Depressed, Uniform, Dropshadow]Font Family[select: Proportional Sans-Serif, Monospace Sans-Serif, Proportional Serif, Monospace Serif, Casual, Script, Small Caps]Reset restore all settings to the default valuesDoneClose Modal DialogEnd of dialog window. The code shown below is the code for the crab sprite. It is incomplete. Complete the code for the crab sprite to produce the desired effect. 1. 2. 3. 4.

Question

BlackTom AI · Accepted Answer

Facing upward in Scratch is direction 0 and facing downward is direction 180, so the program must test mouse y relative to the crab’s y and rotate toward 0 when the mouse is above and toward 180 when it is below. 1) Relevant knowledge points and concepts - Scratch directions: 0 = up, 90 = right, 180 = down, -90 = left. - Compare mouse y with sprite y to determine whether the pointer is above (mouse y > y) or below (mouse y < y). - Use “repeat until direction = …” with “turn 15 degrees” (clockwise) or “turn -15 degrees” (anticlockwise) to rotate in the required sense. - Switch costumes before/after rotation to show claws closed while rotating and bigger/open when rotation finishes. 2) Step-by-step reasoning - If mouse y > crab y (pointer above): claws must close, rotate clockwise until orientation equals 0, then switch to the bigger/open claws costume. - Clockwise rotation is achieved with positive turn (e.g., turn 15 degrees) repeated until direction = 0. - If mouse y < crab y (pointer below): claws must close, rotate anti‑clockwise until orientation equals 180, then switch to bigger/open claws. - Anti‑clockwise rotation is achieved with negative turn (e.g., turn -15 degrees) repeated until direction = 180. 3) Intermediate steps / code behavior - Test: mouse y > y position? - Yes: switch to closed-claws costume; repeat until direction = 0: turn 15 degrees; after loop switch to open/bigger costume. - Else test: mouse y < y position? - Yes: switch to closed-claws costume; repeat until direction = 180: turn -15 degrees; after loop switch to open/bigger costume. 4) Why the correct answer is correct Option 4 supplies the comparisons and direction targets that match the intended behavior: it checks mouse y vs sprite y, uses direction = 0 for “above” and direction = 180 for “below”, and the corresponding clockwise/anticlockwise turning leads the crab to face up or down before changing the costume. 5) Why the other options are incorrect - Option 1 uses directions 90 and -90 (right/left) instead of 0 and 180, so it would face sideways rather than up/down. - Option 2 tests mouse x vs x (left/right) so it reacts to horizontal position instead of vertical. - Option 3 swaps or incorrectly assigns 0 and 180 (or otherwise mismatches the required targets), making the crab face the wrong way for the mouse being above/below. 6) Conclusion Therefore the correct choice that implements the required checks and rotations is option 4, matching the provided answer.

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