Immediately after the aphids were placed on the plant it was observed that: • all the aphids ingested the same volume of liquid from the phloem • aphid D ingested the highest concentration of sucrose. Explain why aphid D ingested the highest concentration of sucrose.

Higher concentration in the stem / aphid D is nearer the root / is before the branching of the plant ; (sucrose moves by) translocation ; sucrose moves up the plant ; root / tuber, is a source ; (leaves / stems / AW) are a sink ; no photosynthesis (in the dark) ; no / less, glucose/sucrose (made in the leaves) ; plant uses stored starch (from root) / AW ;