<em>Hardness is a measure of how resistant solid matter is to various kinds of permanent shape change when a force is applied</em> <em>Macroscopic hardness is generally characterized by</em> <em>strong intermolecular bonds</em>, <em>but the behavior of solid materials under force is complex; therefore,</em> <em>there are different measurements of hardness</em>: <em>scratch hardness, indentation hardness, and rebound hardness. Hardness is dependent on ductility, elastic stiffness, plasticity, strain, strength, toughness, viscoelasticity, and viscosity. Common examples of hard matter are ceramics, concrete, certain metals, and super hard materials, which can be contrasted with soft matter.</em>
Answer:
The development of refrigeration and frozen-food technology has benefited society in the following ways.
1) Refrigerator helps the people to protect the food substance from the infection of microorganisms such as bacteria and fungi.
2) Refrigerator helps in increasing the shelf life of many food materials. Some food substance have very short shelf life which can be increased by placing in the refrigerator.
Chicken sausages, nuggets and meat boll are the products that developed because of frozen -food technology.
1 - They all are solids due to the strong electrostatic force
<span>2 - They also have high m.p and b.p. </span>
<span>3 - It conduct electricity in molten state or in aqueous solutions </span>
Microorganisms can be divided into two groups:
1. Archea
• Archea are prokaryotic unicellular organisms without cell nucleus or other membrane bound-organelles.
• Their membrane is built from ether lipids, which differs them from bacteria’s cell membrane.
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2. Bacteria
• Bacteria are also unicellular prokaryotic organisms.
• Bacterial cell membranes are made from phosphoglycerides with ester bonds. Bacterial genome is in a form of circular chromosome.
• They reproduce by binary fission or by budding.
Besides, prokaryotes (Archea and Bacteria) a large number of eukaryotes are also microorganisms. Unicellular eukaryotes contain organelles such as the cell nucleus, the Golgi apparatus and mitochondria. Usually, they reproduce asexually by mitosis. An example of eukaryotic microorganism is Protist.