Sieve cells
Tracheids
Gymnosperms are a group of seed-producing plants that includes conifers, cycads, Ginkgo, and Gnetales. They are characterized by the absence of flowers and fruits, and their seeds are not enclosed within an ovary (hence the term "gymnosperm" which means "naked seeds"). To determine what is not found in gymnosperms, let's examine the options:
Based on the examination of these options, the correct answer is Vessels. This is because vessels are absent in most gymnosperms, whereas the other components (sieve cells, albuminous cells, and tracheids) are present.
Thus, the option not found in gymnosperms is vessels.
| Pair of skeletal parts | Category | |
|---|---|---|
| (a)$\,\,$ | Sternum and ribs$\,\,$ | Axial skeleton |
| (b)$\,\,$ | Clavicle and glenoid cavity$\,\,$ | Pelvic girdle |
| (c)$\,\,$ | Flumerus and ulna$\,\,$ | Appendicular skeleton |
| (d)$\,\,$ | Malleus and stapes$\,\,$ | Ear ossicles |