- 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.
Doubt clarification - use comment section.
Answer:
1/2
Explanation:
Genotype of the heterozygous mother= X^cX
Genotype of color-blind father= X^cY
A cross between heterozygous mother and color blind father would give progeny in following phenotype ratio=
1 colorblind daughter: 1 colorblind son: 1 carrier but normal daughter: 1 normal son.
Therefore, this couple has 1/2 probability of getting a colorblind daughter is 1/2
For the answer to the question above, the <span>head circumference is a means of assessing brain growth.
It means that even though her daughter is premature. She's growing normally and without any brain problem or whatsoever and she's healthy.
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It is because all these three elements contain ionic properties and they have only one element in their outermost shell
