A focus group is an interview conducted by a trained moderator among a small group of respondents in an unstructured and natural manner.
SUBSTANCE: Material composed of only one kind of matter throughout (same atoms or same molecules) ELEMENT: A substance that cannot be decomposed (broken down) into simpler substances by ordinary chemical means. Examples: gold, iron, carbon, hydrogen, oxygen, nitrogen.
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Variegated leaves have green parts (where the cells contain chlorophyll) and white parts (where there is no chlorophyll). Only the parts that were green become blue/black with iodine solution, showing the importance of chlorophyll in photosynthesis. ... This is evidence that chlorophyll is required for photosynthesis.