Science, asked by memonmusa2009, 8 months ago

1. Explain different types of fibres. Define and give examples.

3. Explain any 2 types of joints with a neat labeled diagram.
4. Study the figure and answer the following question

a. Identify the blanks from the figure

b. Define pistil.​

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Answers

Answered by kalivyasapalepu99
0

1. Fiber or fibre (from Latin: fibra) is a natural or man-made substance that is significantly longer than it is wide. Fibers are often used in the manufacture of other materials. The strongest engineering materials often incorporate fibers, for example carbon fiber and ultra-high-molecular-weight polyethylene.

3. Ball and socket joint.

Hinge joint.

Condyloid joint.

Pivot joint.

Gliding joint.

Saddle joint.

4- a. Nyctalopia (/ˌnɪktəˈloʊpiə/ from Greek νύκτ- (nykt-), meaning 'night', ἀλαός (alaos), meaning 'blind, not seeing', and ὄψ (ops), meaning 'eye'),[1] also called night-blindness, is a condition making it difficult or impossible to see in relatively low light. It is a symptom of several eye diseases. Night blindness may exist from birth, or be caused by injury or malnutrition (for example, vitamin A deficiency). It can be described as insufficient adaptation to darkness. Scurvy is a disease resulting from a lack of vitamin C (ascorbic acid).[1] Early symptoms of deficiency include weakness, feeling tired and sore arms and legs.[1][2] Without treatment, decreased red blood cells, gum disease, changes to hair, and bleeding from the skin may occur.[1][3] As scurvy worsens there can be poor wound healing, personality changes, and finally death from infection or bleeding.[2]

b. The pistils of a flower are considered to be composed of carpels.[note 1] A carpel is the female reproductive part of the flower, interpreted as modified leaves that bear structures called ovules, inside which the egg cells ultimately form and composed of ovary, style and stigma. A pistil may consist of one carpel, with its ovary, style and stigma, or several carpels may be joined together with a single ovary, the whole unit called a pistil. The gynoecium may consist of one or more uni-carpellate (with one carpel) pistils, or of one multi-carpellate pistil. The number of carpels is described by terms such as tricarpellate (three carpels).

Carpels are thought to be phylogenetically derived from ovule-bearing leaves or leaf homologues (megasporophylls), which evolved to form a closed structure containing the ovules. This structure is typically rolled and fused along the margin.

Although many flowers satisfy the above definition of a carpel, there are also flowers that do not have carpels according to this definition because in these flowers the ovule(s), although enclosed, are borne directly on the shoot apex.[5][10] Different remedies have been suggested for this problem. An easy remedy that applies to most cases is to redefine the carpel as an appendage that encloses ovule(s) and may or may not bear them.[6][7][11]

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