1 Coelomate animals or Coelomata (also known as eucoelomates â true coelom) have a fluid filled body cavity called a coelom /ËsiËlÉm/ with a complete lining called peritoneum derived from mesoderm (one of the three primary tissue layers).he coelom allows muscles to grow independently of the body wall â this feature can be seen in the digestive tract of tardigrades (also known as water bears) which is suspended within the body in the mesentery derived from a mesoderm-lined coelom.
At a 3 percent growth rate, its doubling time â or the number of years to double in size â is 23 years. (The doubling time for a population can be roughly determined by dividing the current growth rate into the number 69. Therefore, 69/3=23 years. Of course, if a population's growth rate does not remain at this rate, the projected doubling time would need to be recalculated.)
During the 1990s, Vietnam experienced a sharp decline in its population growth rate: from nearly 2 percent at that beginning of the decade to 1.4 percent by 2000. A growth rate of 2 percent, if maintained, would double a population in 35 years, but a rate of 1.4 percent would require 50 years.