Domain: Engineering — Agricultural Engineering
Target concept: Peeling the soybean seed coat and observing it confirmed the absence of endosperm. The two cotyledons enclose the hypocotyl/radicle and fill the interior of the seed coat.

Video generation prompt: Show a hand holding a dry soybean seed. Use forceps to remove the seed coat. Separate and open the seed to expose its internal structure. The procedure is clear and the steps are logical, with a focus on seed dissection.

Evaluation guide:
(i) Target concept: Visual confirmation of soybean seed anatomy as a non-endospermic dicot through direct dissection.
Minimum mechanism: Dry soybean seed must retain intact morphology (no hydration-induced swelling); the seed coat, though firmly adhered on a fully dry seed, must be capable of being loosened and peeled away with careful mechanical action (forceps prying/scraping), even if it comes away in a couple of fragments rather than one intact sheet, without damaging the cotyledons beneath; and the cotyledons must physically enclose the embryonic axis, which becomes visible only once mechanical separation occurs.
(ii)Storyline: Frame opens on hand holding intact dry soybean seed → forceps approaches and makes contact with seed coat → seed coat detaches and moves away → hand or forceps gently separates two cotyledons → cotyledons splay outward symmetrically → central embryonic axis becomes fully visible between them; all events occur in fixed frontal close-up view with no camera movement, no cut, and consistent lighting; embryonic axis must not be visible prior to separation, and endosperm must never appear.

Manual:
Experimental Procedure
1. Hand holds a dry soybean seed.
2. Forceps grip and peel away the seed coat, which is firmly adhered on a fully dry seed and may come away in one piece or a few fragments with careful prying/scraping.
3. Cotyledons are separated and splayed open to expose internal structure.
Observation of Experimental Phenomena
- Seed coat is thin and papery; once loosened it detaches from the seed body, possibly in a couple of fragments rather than a single sheet.
- Two fleshy, pale-yellow cotyledons fill the seed interior completely.
- No endosperm visible between or around cotyledons.
- Hypocotyl and radicle are enclosed centrally, visible only after cotyledons are separated.
Summary of Experimental Principles
Soybean is a dicotyledonous, non-endospermic seed: the embryo consists of two cotyledons that store oil and protein reserves and enclose the embryonic axis (hypocotyl + radicle); the seed coat is the sole protective layer; endosperm is absent in mature seeds.

Prompt Grounding rubric:
level_1: No hand, no soybean seed, no forceps, and no exposed interior of the seed ever appear; none of the four key elements (hand, dry soybean seed, forceps, an opened interior showing two halves) are shown in the clip.
level_2: At least one of the four elements (hand, seed, forceps, exposed interior) appears, but the clip never shows the progression of holding the seed, then removing the seed coat with forceps, then separating the cotyledons: the actions are missing, out of order, or it's unclear the object is even a seed.
level_3: A hand holds a soybean seed, forceps make contact with and remove the seed coat, and the two cotyledons are separated and opened to reveal the interior; all four elements appear and the three actions happen in the right order, but at least one step lacks a clear visual follow-through (for example, the seed coat is simply gone in the next shot without showing it lift away, or the cotyledons are apart but it's unclear they were pulled apart from each other rather than always being loose).
level_4: Meets all the level-3 requirements above, and additionally: the hand is seen holding the seed before the forceps engage it, the forceps are seen gripping and lifting the seed coat away from the seed body, the seed coat is absent from the seed once removed, and the two cotyledons are seen fully separated and opened to show what's inside, with no step skipped or shown only as a before/after cut, and the seed recognizable as a soybean rather than some other type of bean.
level_5: Meets all the level-4 requirements above, and additionally: the seed coat visibly separates from the seed body during the shown forceps action (rather than appearing already detached), and it isn't left covering most of the seed's surface afterward; both cotyledons end up clearly separated and spread apart from each other rather than merely cracked open while still joined; and the space between them is unobstructed by the hand, forceps, or leftover seed-coat fragments in the final view.

Scientific and Causal Correctness rubric:
level_1: The video shows a separate translucent or starchy-looking tissue layer between the two cotyledons (endosperm-like tissue), or only one cotyledon is ever shown, or the two cotyledons are shown still fused together with no separation, or the seed shown is clearly green/immature or already germinating with an elongated radicle, any of which contradicts a mature soybean seed's two-cotyledon, non-endospermic anatomy.
level_2: The seed coat is removed and the cotyledons are separated, but there's an anatomical inconsistency: the cotyledons are the wrong color for a mature dry soybean (bright green or pure white rather than pale yellow/cream), or a visible extra tissue layer sits between the seed coat and the cotyledons, or the embryonic axis (hypocotyl/radicle) is entirely absent once the cotyledons are opened.
level_3: The seed coat is fully removed, the two cotyledons are visibly separated, and no separate endosperm-like layer is shown between them, but the embryonic axis stays mostly hidden between the cotyledons rather than clearly visible, or the two cotyledons look noticeably uneven in size or shape.
level_4: Meets all the level-3 requirements above, and additionally: both cotyledons are similar in size and fully fill the space the seed coat had enclosed, and once separated they clearly reveal a small embryonic axis (hypocotyl and radicle) at the point where they had been joined, with no endosperm-like tissue visible anywhere and no torn or fragmented cotyledon suggesting mishandling rather than a real structural feature.
level_5: Meets all the level-4 requirements above, and additionally: the embryonic axis stays hidden between the two cotyledons until they're pulled apart, becoming visible only once separation happens; the cotyledons keep a firm, fleshy, oil-and-protein-rich look rather than a starchy, shriveled, or translucent one; and no seed-coat fragments or extra membrane are left clinging to the cotyledons or visible between them.

Spatiotemporal Consistency rubric:
level_1: The seed, hand, or forceps appears to jump to a different position or vanish and reappear; the seed rotates by more than 90° instantly with no turning motion shown; the lighting on the seed and hand flickers or shifts with no visible cause; or the background changes or flickers.
level_2: A major continuity break occurs: the seed coat is shown attached, then in the very next moment already removed with no detachment motion shown; the cotyledons go from closed to fully open with no in-between spreading motion; the hand appears already holding an already-opened seed at the very start with no lead-up shown; or the camera cuts or zooms abruptly mid-action.
level_3: The hand, seed, forceps, and cotyledons stay arranged the same way relative to each other throughout, with nothing swapping position or disappearing; the hand keeps a steady hold on the seed; the forceps move toward the seed coat and away again after removing it; the cotyledons open up gradually with a visible spreading motion, though there may be minor issues like a slight wobble in the hand or the seed briefly passing behind the forceps during separation.
level_4: Meets all the level-3 requirements above, and additionally: there are no jumps, no cuts, and no lighting changes anywhere in the clip; the hand holds the seed steadily without drifting; the forceps approach, grip, and lift the seed coat away in one unbroken motion, and the detached coat moves clear of the seed rather than falling back onto it; the two cotyledons separate fully and symmetrically in one continuous motion; and the camera keeps the same fixed, close-up framing throughout.
level_5: Meets all the level-4 requirements above, and additionally: the whole sequence (hand holding, forceps lifting the coat, cotyledons spreading) looks fluid with no stutter or motion-blur glitches; the hand, forceps, and seed keep a believable, unchanging depth relationship to one another (nothing appears to float in front of or behind where it should be); the shadows on the seed and hand fall consistently from a single implied light source throughout; and there's no visible sign of an edited-in artifact (no doubled edges, no flicker) during the seed-coat removal or cotyledon separation.