Vitamins and Human Biology Quiz

Sharks are fish, not mammals. They have gills for breathing underwater, are cold-blooded, and most species lay eggs (though some give live birth). Mammals have lungs, are warm-blooded, and typically nurse their young with milk. Sharks belong to the class Chondrichthyes (cartilaginous fish).

The adult human skeleton typically contains 206 bones. This number decreases from approximately 270 bones at birth, as many bones fuse together during growth. Therefore, the statement that the skeleton has less than 100 bones is false.

Vitamin K is essential for blood clotting as it helps produce clotting factors in the liver. The 'K' comes from the German word 'Koagulation' meaning clotting.

Vitamin A deficiency is the leading cause of preventable childhood blindness worldwide. It causes a condition called xerophthalmia where the eyes cannot produce tears and the cornea becomes damaged.

Folate (Vitamin B9) is essential for DNA synthesis and cell division. It's particularly important during periods of rapid growth like pregnancy and fetal development.

Vitamin E is a fat-soluble antioxidant that protects cell membranes from oxidative damage by neutralizing free radicals. It's one of the body's primary defense mechanisms against oxidative stress.

Vitamin D receptors are found throughout the body and play a crucial role in regulating cell differentiation and proliferation. Beyond bone health, Vitamin D helps control cell growth and immune function.

Vitamin D plays a crucial role in controlling cell differentiation and proliferation through its nuclear receptor (VDR), which regulates gene expression. It helps maintain proper cell growth and prevents abnormal proliferation. Vitamin D deficiency has been linked to various cancers and autoimmune disorders.

Ireland is famously known for having no native snake species. This is due to its geographic isolation and post-glacial climate - snakes never managed to recolonize the island after the last Ice Age. The other options are problematic: California is a US state, not a country; West Indies is a region; and Borneo is an island shared by multiple countries. Ireland is the only correct option as a country without native snakes.