In the days of feudalism, when noblemen gathered for a meal in the castle, those of higher rank sat at the head of a T-shaped table, and the rest sat in order of diminishing importance away from them.
For such occasions a yard-long loaf of bread was baked, and the honour of making the first cut belonged to the highest-ranking person at the head table, who would then pass the bread down in order of rank, but always keeping for himself the “upper crust.”
Yes, for a period of time. The mangrove killfish spends several months of every year out of the water, living inside rotting branches and tree trunks. The 2-inch- (5-centimeter-) long fish normally lives in muddy pools and the flooded burrows of crabs in the mangrove swamps of Florida, Latin America, and the Caribbean. When their pools of water dry up, they temporarily alter their gills to retain water and nutrients, while they excrete nitrogen waste through their skin.
These changes are reversed as soon as they return to the water. The mangrove killfish is not the only fish able to temporarily survive out of water. The walking catfish of Southeast Asia has gills that allow it to breathe in air and in water. The giant mudskippers of Southeast Asia breathe through their gills underwater and breathe air on land by absorbing oxygen through their skin and the back of the mouth and throat.
Beginning in the Middle Ages, Boxing Day was known as St. Stephen’s Day in honour of the first Christian martyr. Although unknown in the United States, Boxing Day is still observed in Britain, Canada, New Zealand, and Australia.
It’s called “Boxing Day” because on the day after Christmas, the well-off boxed up gifts to give to their servants and tradespeople, while the churches opened their charity boxes to the poor.
The combine harvester saves the farmers time and labor. Before modern machinery, harvesting crops was a painstaking process. Gathering and removing mature plants from the field had to be done by hand. Farm workers used sharp-bladed, long-handled scythes and curved sickles to cut down cereal crops like wheat. Even the fastest reaper could only clear about a third of an acre a day. Because rain could ruin harvested wheat, workers called sheaf-makers quickly tied it into bundles, so that it could be safely stored if the weather turned stormy. During the long winter months farm workers used jointed wooden tools called flails to thresh or beat the dried wheat in order to separate its edible grain seeds from its stalks.
But in 1786 a machine that threshed wheat by rubbing it between rollers was invented, replacing human threshers. And around 1840 a reaping machine—whose revolving wheel pressed grain stalks against a sharp blade that cut them down— replaced human harvesters. Today, farm machines called combine harvesters do this work in much the same way. These machines are very efficient and combine all three jobs of cutting, collecting, and threshing a crop. A single combine harvester can process five acres of wheat in less than an hour!
Since flowers possess both male and female parts, some flowers can fertilize themselves— or fertilize another flower on the same plant—which is called self-pollination. Or the ovules of one flower may be fertilized by the pollen of a different flowering plant of the same species, a method called cross-pollination.
The wind, water, insects, and other animals help to carry pollen from one flower to another. Crosspollination usually produces a better plant: the offspring of cross-pollination possesses the genetic traits of two parents, which may give it new characteristics that will help it survive in an always-changing environment. Cross-pollination is so desirable, in fact, that many flowering plants have developed different ways to keep selfpollination from happening. In the flowers of a spiderwort plant, for example, the stamens are ready to release pollen grains before the pistils are ready to accept them, so the pollen has to travel to other spiderwort plants in search of a ripe pistil.
Muscles are attached to bones by tendons, the longest and strongest of which is called the Achilles tendon in your heel. This thick band of tissue attaches the muscles of the calf to the heel bone and is the key to the foot’s ability to flex.
The Achilles tendon allows you to push off of your foot when walking or running. In ancient Greek myth, the hero Achilles died from a wound to his heel, so the popular expression “Achilles heel” often refers to a physical weakness or limitation.