The diagram illustrates the relationship between phloem sieve tube elements, xylem vessel elements and companion cells. Which row correctly shows what the numbers 1, 2, 3, 4 and 5 could stand for?
- A1 companion cells; 2 endoplasmic reticulum; 3 phloem sieve tube elements; 4 no nucleus; 5 xylem vessel elements
- B1 companion cells; 2 nucleus; 3 phloem sieve tube elements; 4 cytoplasm; 5 xylem vessel elements
- C1 phloem sieve tube elements; 2 mitochondria; 3 companion cells; 4 nucleus; 5 xylem vessel elements
- D1 xylem vessel elements; 2 no cytoplasm; 3 phloem sieve tube elements; 4 vacuole; 5 companion cells