(i) Pili and fimbriae are the two surface extensions that are not concerned with motility.
(ii) Structure that helps in motility of bacterial cell is flagella.

At hills, the pressure of air falls and the person cannot get enough oxygen in the lungs for diffusion into the blood.Due to deficiency of oxygen, the person feels breathlessness, headche, dizziness, nausea, mental fatigue and a bluish colour on the skin, nails and lips.

Bile is a yellowish green alkaline solution with 89-98% water, it has no digestive enzymes.the bile released into the duodenum contains bile pigments(bilirubin and biliverdin), bile salts, cholesterol and phospholipids, but no enzymes.Bile helps in emulsification of fats, i.e breaking down of the fats into very small micelles.Bile also activates lipases.

Amylase acts on starch which is not a constituent of any tissue lining the gut, so, there is no need for it to be secreted in an inactive form. Whereas, the trypsin is a protease that can hydrolyse the cellular and intercellular proteins of the gut wall in the absence of food. So, it has to be secreted in an inactive form.

Cut leaves in cytokinins stayzreen for longer duration because cytokinins retard ageng of plant organs by promoting protein synthesis aid mobilisation of nutrient resources.

the stepwise release of energy have advantage to the cell. Because if all the energy from the glucose would be released at once then most of it would be lost in the form of light and heat. This energy is trapped in ATP is utilised in various energy-requiring processes of the organisms and for the synthesis of the other biomolecules in the cell.

Plants require various minerals for their normal growth, development and metabolism.It means that all essential elements must be present in soil or in the air, water etc., wherever the plant grows.
Now, if any particular element or a group of element is supposed to be missing in the soil or in the atmosphere, the element will be deficient to that plant and the plant will eventually die of some or the other deficiency.

Synapse acts as a one-way valve because neurotransmitter is secreated at the terminal knobs of axon only. The dendrite membarane (postsynaptic membrane) has the specifice protein receptor molecules to break this neurotransmitter.

On reducing or removing the fifty per cent of leaves from plant, the rate of transpiration by the remaining leaves will decreases because the rate of transpiration is purely dependent upon the surface area of the leaves. Thus, plant with larger leaf surface area have higher rate of transpiration as compared to the plant with the areas of smaller leaf surface 

An analysis of the xylem exudates shows that through some of the nitrogen travels as inorganic travels as inorganic ions, much of it is carried in the organic form as amino acids and related compounds. Similarly, small amount of phosphorus and sulphur are carried as organic compunds.In addition, small amount of exchange of materials does take between xylem and phloem.

Gene expression, protein synthesis, secretion, motility etc, do not happen during M-phase.

Starch consists of two components i.e., unbranched spirally coiled amylose molecules and branched amylopectin molecules. Both are glucose polymers hence it is called as homopolysaccharide.

Polyunsaturated oils contain fatty acids having one or more double bonds, the clotting property of blood decreases due to high proportions of PUFA. Thus, the possibility of blockage is reduced.

The body of a multicellular organism has cell as a basic structural unit. The cells are organised to form tissues such as blood, bone, etc. The tissue are organised to form organs such as heart, kidney, etc. The organs are then organised to form organ systems such as digestive system, reproductive system respiratory system, etc. The various organ system of organism gets arranged to form a complete individual.

Animal cells have an interior membrane that delimits a cell nucleus thus, they are eukaryotic cells. In these cells, the genetic material is located within the nucleolus whereas, the bacterial cells do not have organised cellular nuclei so, are called prokaryotic cells.

The bones have excessive calcification . So it is difficult to sty living cells in an untreated bones. For their study , the bone id first decacified in the same way as architecture of the matrix is studied after drying up of the living materials.

Closed circulatory is found in most annelids and all vertebrates. In these groups blood flows at faster speed and high pressure due to force provided by the rythmic contraction and relaxation of heart muscles.

microsporophyll of gymnosperms  It is broad and not distinguished into filament and anther.
microsporophyll of angiosperms It consists of a filament and a terminal anther.

Gymnosperms and angiosperms are classified separately although they both bear seed because of following reasons
i) Ovules in gymnosperms are naked. In angiosperms, they are enclosed inside the ovary.
ii) Wood is non-porous in gymnosperms,i.e, the vessels are absent. Wood in angiosperms is porous,i.e, the vessels are present.

The artificial system of classification was mainly based on vegetative characters or on the androcium structure (system given by Linnaeus). Such system separated the closely related species since they were based on a few characteristics. The artificial system gives equal weight to vegetative and sexual characteristics. This is not convincing because the vegetative characters are more easily affected by the environment.

When female mosquito like Anopheles, suck human blood, it simultaneously injects a poisonous liquid containig protozoan cells into our blood. This poison causes the itching and causes swelling of the area.

Bracket or shelf fungi are lignocolous fungi which produce bracket or shelf-shaped, hard, leathery basidiocarps that are found to come out from the tree trunk on loss of wood, e.g., Fomes tomentarius, etc.

Species is the lowest of a population or basic taxonomic category which consists of one or more individuals that resemble one another more closely than individuals of other species.
The members of a species interbreed freely and are reproductively isolated from members of other species. These features make the species basic taxonomic category.

There are diverse habitats on earth hosting millions of living organisms. Due to limited number of taxonomists, absence of thorough survey of different areas and occurrence of several inaccessible regions, e.g., hot springs, underwater reefs, etc., it is difficult to identify all the organisms.