- Xylem contains tracheids, vessels, xylem parenchyma and xylem fibre.
- Tracheids: They are elongated, tubular dead cells with tapering end walls.
- Vessels: These are also known as trachea. They are elongated, tubular dead cells. They are joined to each other by end to end forming a continuous pipe. The cells are thick and lignified.
- Xylem parenchyma: They are also called wood parenchyma. This is the only living tissue of xylem.
- Xylem fibre: They are dead cells with thick walled fibre.
- Phloem consists of sieve tubes, companion cells, phloem parenchyma and phloem fibres.
- Sieve tubes: These are elongated, tubular living cells arranged in a row, with their perforated end walls forming a sieve. They are non-nucleated. Their protoplasm are inter-connected through sieve plates. They possess vacuoles.
- Companion cell: They are elongated, lens-shaped cells containing dense cytoplasm and prominent nuclei. These cells maintain connection with sieve cells through pits.
- Phloem parenchyma: They are living thin walled parenchyma cells.
- Phloem fibre: They are also known as bast fibre. They are elongated fibre like sclerenchymatous dead cells with thick walls containing pits and interlocked ends. Phloem fibre are the only dead cells in phloem.
Hope you could get an idea from here.
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There are different star systems. Binary star systems consist of two stars. Multiple star systems consist of two or more stars. The meaning of star system is "A small number of stars."
I think it's either A) a group of hundreds of stars, or B) a group of two or more stars. I would assume it's B), but i could be wrong.
Hope this helps!
Cell membrane is a thin line.it controls the movement of materials into and out of the cell. it is partially permeable,that is,it allows only certain materials to pass through.
The correct answer is D) The remote control transmits information through waves, such as infrared waves, to the television. Therefore a remote needs to be pointed at the tv in order to work.
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