The defecation reflex involves two postive feedback loops. these loops are the stretch receptors in the rectal walls and the sacral parasympathetic system. Defecation reflex empties the rectum by peristaltic movements push fecal matter from the sigmoid colon into the rectum. Then this distension of the rectal walls stimulates stretch receptors which results in defecation.
The answer is true because the signal of a perceiver is a technique to determine the ability.
<span>Peter Raymond Grant, FRS, FRSC, and Barbara Rosemary Grant, FRS, FRSC, are a British couple who are evolutionary biologists at Princeton University. Each currently holds the position of emeritus professor. They are known for their work with Darwin's finches on Daphne Major, one of the Galápagos Islands. Since 1973, the Grants have spent six months of every year capturing, tagging, and taking blood samples from finches on the island. They have worked to show that natural selection can be seen within a single lifetime, or even within a couple of years. Charles Darwin originally thought that natural selection was a long, drawn out process. The Grants have shown that these changes in populations can happen very quickly.</span>
Answer:
The polarity of membrane phospholipids
Explanation:
The inner core of membranes is made of nonpolar tails of phospholipids which in turn makes the membranes impermeable for polar, large and charged substances since these substances cannot cross the non-polar inner core. The saturated hydrocarbon tails pack tightly and make membrane less permeable while cholesterol affects the membrane permeability by interacting with non-polar tails.
Higher temperatures make the membrane more fluid and more permeable while at lower temperatures, membranes are more rigid due to tight packing of hydrocarbon tails and less permeable. The polar heads of phospholipids make the inner and outer surface of the membrane. Therefore, the polarity of phospholipids does not affect the membrane permeability.
Metals are strong, high density, good conductors of heat and electricity, and are also malleable and ductile. While non metals are brittle, dull looking, are poor conductors of heat and electricity, and are overall weaker.