The Thyroid itself secretes three main hormones: 1  Thyroxine contains iodine which is essential for the body's normal growth, and metabolism. 2  Triiodothyronine has similar functions to thyroxine. 3  Calcitonin causes a decrease in the concentration of calcium in the blood.
acre. acre, measure of land area used in the English units of measurement. The acre was originally the area a yoke of oxen could plow in a day and therefore differed in size from one locality to another.It is now fixed as 10 square chains or 160 square rods, i.e., 4,840 sq yd, 43,560 sq ft, or 1/640 sq mi. Share | Cite. acre, measure of land area used in the English units of measurement. The acre was originally the area a yoke of oxen could plow in a day and therefore differed in size from one locality to another. It is now fixed as 10 square chains or 160 square rods, i.e., 4,840 sq yd, 43,560 sq ft, or 1/640 sq mi.
Written By: Acre, unit of land measurement in the British Imperial and United States Customary systems, equal to 43,560 square feet, or 160 square rods. One acre is equivalent to 0.4047 hectares (4,047 square metres). Derived from Middle English aker (from Old English aecer) and akin to Latin ager (âfieldâ), the acre had one origin in the typical area that could be plowed in one day with a yoke of oxen pulling a wooden plow.