Arabidopsis contains how many phytochrome isoforms?
Correct option is D, Five. In PHYTOCHROME problems like this, the accurate statement is Five; the others are common mix-ups. Not these: A) Two; B) Three; C) Four. Tissue transport questions usually turn on xylem vs phloem, living vs dead cells, or source vs sink.
Ref: Best CSIR NET Plant Physiology books: Master Unit 6 with Taiz & Zeiger and Salisbury & Ross. Crack Part C experimental questions with top textbooks.