4. Give reason for the following-
(a) Blood is considered as connective tissue.
(b) the growth of plants occur only in certain specific regions
(c) intercellular spaces are absent in scleranchymatous tissues.
(d) Meristematic cells have a prominent nucleus and dense cytoplaom but they lack vacuole.
(e) We get crunchy and granular feeling, when we chew pear fruit.
Answers
Answer:
(a) BLOOD: It is considered a connective tissue, because it consists of blood cells surrounded by a nonliving fluid matrix called blood plasma. It is the most atypical connective tissue: the fibers of blood are soluble protein molecules that become visible during blood clotting.
(b)The growth of plants occur in speciic regions due to the presence of meristematic tissue in those speciic regions because the meristematic tissue is the one which is responsible for the division in plants. ... In other regions the meristematic tissue is absent. So, Growth occurs only in certain speciic regions.
(c) Intercellular spaces are absent in sclerenchymatous tissues because they have a cementing substance (known as lignin) around their cell membrane which makes them stiff and hard.
(d) Since meristematic tissue cells are very active, they have thick cytoplasm, thin cellulose walls, and prominent nucleus. Vacuoles are full of cell sap in plant cells and provide the cell with turgidity and stiffness. Meristematic cells are therefore deficient in vacuoles since they are actively dividing the cells.
(e) Pear contains cells of sclerenchyma which are small, rounded and called stone cells. They are hard with highly thickened cell wall. These cells give the crunchy and granular feeling when we chew pear fruit.
Answer:
Hence,
A) Blood is considered a connective tissue because it has matrix...... Blood tissue.
B) The growth of plants occurs only in certain specific regions. This is because the dividing tissue, also known as meristematic tissue, is located only at these points.
C) intracellular speces are absent in sclerenchymatous tissue. sclerenchyma is the tissue that gives the plant it's stiffness and hardness.. sclerenchyma is the plant support tissue. sclerenchyma cells are divided into two types : cellular fibres and sclereids.