The correct answer is option b, that is, the addition of carbon dioxide to the atmosphere.
If the concentration of carbon dioxide upsurges in the atmosphere due to the enhanced rate of outgassing, there will be a constant elevation in the global temperature. The elevating temperature and more dissolved carbon dioxide will result in enhanced weathering of crystal rocks as a consequence of faster rate of reactions and greater acidity.
Sorry for a late answer... But here we go!
https://www.sciencelearn.org.nz/resources/102-methods-of-pollination
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.
number 8 is b because when you eat plants or animals, it get transfred to glucose which is then transfered to atp. Think about it this way, when you are sick, you dont just go outside in the sun to recharge and then you suddenly get better, and energy, you have to rest and eat certain foods that will restore your ATP levles.