A mother who is blood type O can only pass an O allele to her son or daughter. A father who is blood type AB could pass either an A or a B allele to his son or daughter. This couple could have children of either blood type A (O from mother and A from father) or blood type B (O from mother and B from father).
At night, humans can use flashlights to spot animals that possess tapetum lucida by causing a phenomenon called eye shine.. Eye shine is the iridescent glow observed in animals when light is shone into their eyes, which floods the eye with light that is then reflected by the tapetum lucidum.
The most common known causes of eye twitch include fatigue, stress, anxiety, and excessive caffeine intake. Eyelid twitch may appear in response to irritation caused by smoke, dust, or a foreign body in the eye. Allergies and infections may also cause irritation that leads to twitching. Eyelid twitch is seen in primary congenital glaucoma.