Question: Idan wani muhalli ya zama mai zafi da kuma bushewa, sauyin da zai fi yiyuwar taimakawa halittu su rayu shine su ƙara yawan .......... ɗinsu.
Options:
adadin yawan kitsen jiki
adadin gashin jiki
iya hawa bishiyoyi 
iya adana ruwa
Answer: D