The mechanisms of reproductive isolation prevent the reproduction of two individuals from different species. The prezygotic mechanisms disrupt the stages of reproduction before the forming of the zygote or prevent the mating at the start, and the postzygotic mechanisms affect the stages of reproduction after the forming of the zygote.
So, the first and the third example (the urchins and the grasshoppers) show the prezygotic mechanism, as the two individuals are not able to mate or form a zygote.
The second and the fourth example ( zonkey and the death of a zygote) show the working of the postzygotic mechanisms, as the zygote is formed, but it seems to be inviable, and the zonkeys are sterile, preventing the individual to reproduce.
Answer:
The geocentric model says that the earth is at the center of the cosmos or universe, and the planets, the sun and the moon, and the stars circles around it. The early heliocentric models consider the sun as the center, and the planets revolve around the sun.
Explanation:
The question is incomplete as it does not have the options which are:
A. 8; 32
B. 10; 29
C. 12; 20
D. 5; 45
Answer:
The correct answer will be option-B
Explanation:
Trauma is the experience caused by the life-threatening events or events which help develop the psychological distress conditions.
The trauma can cause changes in the physiologic and psychological responses in humans. The CDC guidelines have stated criterion for immediate transportation of the person to the trauma centre in which one of the criteria is that if a person has the respiratory rate of less than 10 and greater than 29 will be transported to the trauma centre immediately.
Thus, Option-B is the correct answer.
Apples are a fruit that is high in fiber, vitamin C and various antioxidants. It has vitamins and minerals.
Answer:
1.Take all of your medicines as they're prescribed, until your doctor takes you off them.
2.Keep all your doctor appointments.
3.Always cover your mouth with a tissue when you cough or sneeze. ...
4.Wash your hands after coughing or sneezing.
5.Don't visit other people and don't invite them to visit you.