Answer:
The correct answer is: upper esophageal sphincter.
Explanation:
The alimentary canal is a very long tract responsible for the digestion of the food. It is composed of several organs with many different and important functions. The alimentary canal also has a few sphincters, which are muscular valves that open and close when needed for the food to pass or be retained.
The first sphincter is the upper esophageal sphincter. One particularity of this sphincter is that is one of the few sphincters in the body that opens and closes under our conscious control, which happens when we decide to swallow our food.
From the first to the last, the order of the sphincters in the gastrointestinal tract is: upper esophageal sphincter, lower esophageal sphincter or gastroesophageal sphincter, pyloric sphincter, ileocecal sphincter, and anus.
Answer: A. scalp hairs grow constantly throughout life.
Explanation:
Hair is a squamous keratinized epithelium which is consist of multi-layered flat cells. Hair are made up of protein called "keratin".
The statement "scalp hairs grow constantly throughout life" is false because at a particular age or due to several factors scalp hairs stop growing.
Scalp hair growth rate depends on three main factors including sex (female hair grows faster than male), age (hair growth slows with age), and ethnicity (Asian hair grows slower than Caucasian hair).
Scalp hair growth stops because of follicle devitalization when the hair length become two or three feet.
Hence, the correct answer is A. "scalp hairs grow constantly throughout life".
There is a difference in color between the reactants and the product. Also, a gas and a solid bread loaf were produced, compared to the liquid or powder forms of the reactants.
The knowledge gained will lead to further experimentation that could potentially result in a new use for the drug.
When you cross two heterozygotes with the genotype Aa, the offspring will be: <span>Parents: Aa x Aa</span>
<span>F1 generation: AA Aa Aa aa</span>
<span>This means that ½ of the offspring will be heterozygous, ¼ will be homozygous (dominant) and ¼ will be homozygous (recessive).</span>
