In each of the following questions, choose the pair that correctly shows the singular and plural forms of the noun. Which of the given pairs denotes the correct singular–plural combination?

Explanation:
·         Option A (Correct): ecosystem → ecosystems (Standard noun ending in a consonant, which takes –s in its plural form). ·         Option B: phenomenon → phenomena (Greek-derived nouns ending in –on change to –a in plural form, not –as). ·         Option C: analysis → analyses (Greek-derived nouns ending in –is change to –es in plural, not –ises). ·         Option D: oasis → oases (Nouns ending in –is change to –es in plural form). ·         Option E: genus → genera (Latin-derived words ending in –us of this class change to –era in plural form).