Goats and sheep belong to the same family but different genera. While they often live together in the same pastures, the hybrid
offspring that are occasionally produced between the two species rarely survive. When such a hybrid does survive, it is usually sterile. Which of the following best explains the mechanism that maintains reproductive isolation between goats and sheep? a. Gene flow is prevented because the two species belong to different trophic levels and therefore do not share a food source.
b. Habitat isolation creates a prezygotic barrier between the two species.
c. The males of one species and the females of the other species are fertile at different times.
d. The two species have a different number of chromosomes, resulting in a postzygotic barrier.
d. The two species have a different number of chromosomes, resulting in a postzygotic barrier.
Explanation:
The two species i.e. sheep and goat have different number of chromosomes that resulting in a postzygotic barrier. Sheep has 56 number of chromosomes whereas goat has 60 number of chromosomes that causes postzygotic barrier in the offspring produced from the fusion of these two species. Postzygotic barrier leads to the creation of a hybrid that is sterile and unable to produce offspring because of difference in chromosome number.
To help relieve heartburn, a person should take medicine that is 'Over-the-counter (OTC) antacids and acid blockers'.
<u>EXPLANATION:</u>
Heartburn is a very common symptom of a condition called Gastroesophageal reflux disease.
This affects the lower part of the esophageal sphincter and also the muscle ring-like connection between the 'esophagus and stomach' which tends to infuse a backward flow of the stomach secretions.
Along with some dietary and life style changes, the intake of antacids and acid blockers can help in the relieve of the symptoms of occasional heartburn.
