Answer:
The correct option is b. lower esophageal sphincter
Explanation:
The esophagus is the initial part of the digestive tract and its function is the transport of the alimentary bolus from the pharynx to the stomach, through the thorax and avoid the reflux thereof. It begins and ends in two sphincter structures, the upper esophageal sphincter and the lower esophageal sphincter, which separate it from the pharynx and stomach. The lower esophageal sphincter has two functions: relax during swallowing and prevent reflux of the gastric contents into the esophagus in the postdeglutory period. After swallowing, there is a relaxation of the lower esophageal sphincter, pressure dropping to levels similar to those of the gastric fundus, which allows the bolus to enter the stomach. This relaxation lasts a few seconds and is followed by a strong contraction that prevents backflow of food.
Answer:
<em>When a baby is born, the zygote has become about </em><em><u>26 </u></em><em>billion cells</em>
Explanation:
Cell: Cell is defined as the structural and functional unit of living thing. I.e The cell is the simplest and the basic unit of life. All living things are made of cell.
Zygote: A zygote is a single cell formed from the union of a male cell called sperm and a female cell called egg.
<em>When a baby is born, the zygote has become about </em><em><u>26 </u></em><em>billion cells</em>
<em></em>
Answer:
The correct answer would be - triploid plant.
Explanation:
Triploidy is a condition which can be defined as the 3 set of chromosome in an organism, the extra set of chromosome may be come from the maternal organism or the paternal derived. Maternal derived triploidy known as the digynic while in in the case of the paternal derived called diandric.
In this case the sperm goes under the meiosis so the each gamete will have one chromosome of each set (I I I) while the egg failed to undergo meiosis so the gamete carry complete set of chromosome ( II II II ) after fertilization the outcome will be Digynic triploidy (III III III).
Thus, the correct answer would be - triploid plant.
The best answer is option D.
Acid rain is simply rainfall that has been rendered acidic due to water vapor reacting with nitrogen oxide ad sulphur dioxide very high up in the atmosphere.
Acid rain is not only a threat to the ecosystem and environment, but also seriously damages buildings and sculptures.
Marble and limestone are especially vulnerable to acid rain. This is because the two building or construction materials contain calcite which is easily dissolved by acid.
Concrete surfaces and paint finishes are also seriously damaged by acid rain.
