Tag: science & technology

Metals conduct electricity because they contain free (delocalized) electrons that can move easily throughout the material when a voltage is applied. The atoms are not lightly packed (metals have close-packed structures), and while many metals do have high melting points, this is not what makes them conductive.

Pressure is a scalar quantity because it has magnitude but no specific direction. It is defined as force per unit area (P = F/A) and acts equally in all directions at a point in a fluid. Force, velocity, and acceleration are all vector quantities with both magnitude and direction.

Infectious mononucleosis, commonly called 'kissing disease' because it spreads through saliva, has several alternate names including glandular fever. Filatov's disease and Pfeiffer's disease (note spelling variation in option) are historical names associated with this condition caused by Epstein-Barr virus.

Malaria is one of humanity's oldest diseases, with evidence of infections found in ancient Egyptian mummies dating back over 4,000 years. The malaria parasite has co-evolved with humans for millennia, making it one of the oldest known infectious diseases still affecting humans today.

Elephantiasis (lymphatic filariasis) is caused by parasitic worms transmitted through the bite of infected mosquitoes, primarily Culex, Anopheles, and Aedes species. The worms block the lymphatic system, causing severe swelling and thickening of the skin and underlying tissues, typically in the legs and genital area.

Anthrax is a communicable infectious disease caused by Bacillus anthracis bacteria. It can spread through contact with infected animals or contaminated animal products, and in rare cases, through inhalation of spores. Wilson's disease is genetic, elephantiasis is vector-borne (not directly person-to-person), and anemia is a non-communicable condition.

Chicken pox (varicella) is a highly communicable viral disease that spreads easily through airborne droplets, direct contact, or contaminated surfaces. It's caused by the varicella-zoster virus. Sleeping sickness and elephantiasis are vector-borne (not directly person-to-person), and pharyngitis can be non-infectious or viral/bacterial but is less definitively communicable than chicken pox.

Pneumonia is an inflammatory condition of the lungs primarily affecting the alveoli (air sacs). It causes these tiny air sacs to fill with fluid or pus, leading to symptoms like cough, fever, and difficulty breathing. The lungs are the primary organ affected, not the liver, intestine, or kidneys.

Herpes (primarily oral herpes caused by HSV-1) typically presents with cold sores or fever blisters around the mouth. The related varicella-zoster virus causes shingles, a painful rash that occurs when the virus reactivates. Local irritation, itching, or tingling often precedes outbreaks. Headache can occur but is not a defining symptom compared to the characteristic skin manifestations.