What is NOT a supporting tissue in plant?

Analyze the question: We are asked to find the option that is NOT a supporting tissue in plants.

Explain the concept: Plants have several tissues that give mechanical support:

• Collenchymas: living cells with unevenly thickened cellulose walls. They support young stems and petioles.
• Sclerenchyma: dead cells with lignified, very thick walls. They give strong rigid support (fibres and sclereids).
• Xylem: its lignified vessels and fibres conduct water and also give strong support, which is why wood is so rigid.
• Parenchyma: thin-walled living cells. They mainly store food and fill space. When they are turgid they give some support to herbaceous plants, but this is not their main role.

Step-by-step solution:

1. Collenchymas is a supporting tissue, so A is not the answer.
2. Sclerenchyma is a supporting tissue, so D is not the answer.
3. Xylem supports as well as conducts, so E is not the answer.
4. Parenchyma is mainly a storage and packing tissue, though it helps support through turgor.
5. Coracoid is not a plant tissue at all. It is a bone in the pectoral (shoulder) girdle of vertebrates such as birds, reptiles and amphibians. It is an animal skeletal structure.

Which is the best answer? The question asks for what is NOT a supporting tissue in plants. Coracoid is not a plant tissue in any sense, so it is clearly not a plant supporting tissue. Parenchyma is arguable, but it does contribute to support through turgidity.

Answer: B. coracoid

Exam tip: When one option comes from a different kingdom or a different topic, as coracoid (vertebrate anatomy) does here, it is often the odd one out. Remember the plant support tissues with "Collenchymas, Sclerenchyma, Xylem" (living flexible support, dead rigid support, and woody support).