- 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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Shallow groove on the surface of the cortex is called sulcus.
Cortex means the outer layer of an inner organ. The outer layer of the cerebrum is called cerebral cortex, where cerebrum occupies the biggest part of the brain. A human being has four lobes of the cerebral cortex which include temporal lobe, parietal lobe, occipital lobe, and frontal lobe.
Cortex has six layers of different types of neurons which are responsible for higher information processing and thinking. Cerebral cortex controls general movement, behavioural reactions, perception and visceral functions. We term the grooved layer as the brain itself.Cerebral cortex consists of large amounts of sulci and gyri(sulcus and gyri in singular). The number of gyri correlates to the processing ability of the animal.A man has big gyri compared to a rat.
<span>Here are the choices: </span>
(a) deletion(b) inversion (c) duplication(d) insertion
Answer: (d) insertion
This mutation occurs when (an) additional nucleotide base pair/s attach themselves into an existing DNA strand. This can possibly result to diseases such as cystic fibrosis and myotonic dystrophy.
Cellular respiration is also a catabolic process because it breaks the small molecules from digestion into even smaller ones as ATP is created. These are both very important processes, because ATP is what your cells use to produce body heat, move your muscles, and other essential bodily functions.
