Types of eye twitching. Minor eyelid twitch also can be caused by irritation of the surface of the eye ( cornea) or the membranes lining the eyelids (conjunctiva). Sometimes the cause of minor eyelid twitch cannot be identified. In almost all cases it is painless and harmless.
Roots are not simply smooth, long structures. In fact, they typically have tiny hairs that cover most of the roots' length. These hairs absorb water and soluble nutrients for plant success. However, some critical nutrients, like phosphorus, are not readily absorbed by plant root hairs. Soil micro-organisms, such as earthworms, consume the surrounding elements and expel castings rich in soluble elements.
18) One important difference between the anatomy of roots and the anatomy of leaves is that. A) only leaves have phloem and only roots have xylem. B) root cells have cell walls and leaf cells do not. C) a waxy cuticle covers leaves but is absent from roots. D) vascular tissue is found in roots but is absent from leaves.