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.
the other measurement often used for surface area is the metric measure hectares a hectare is precisely 100 metres by 100 metres and is much larger than an acre about 2 47 acres make up one hectare so an acre is only about 40 % of the size of a hectarehis is an attempt to help you visualise how big an area one acre is an acre measures an area of land and is about 70 yards by 70 yards which means about 4900 square yards or roughly 44000 square feet