On average, Emu birds can live for approximately how many years under favourable conditions in captivity or the wild?

Introduction / Context:
Emus are large, flightless birds native to Australia and are sometimes farmed in other countries for meat, oil, and feathers. Knowing the approximate life span of such birds is useful in both general knowledge and basic animal husbandry. This question asks about the typical number of years an emu can live under normal, favourable conditions.

Given Data / Assumptions:

• We are considering the average or typical life span, not rare record extremes.
• The options offered are 5, 10, 20, 40, and 2 years.
• We assume reasonable care in captivity or natural survival in the wild.
• The question is framed in a school level general knowledge style.

Concept / Approach:
Emus in the wild usually live for around 10 to 15 years, though some may reach slightly higher ages in protected environments. For exam and quiz purposes, many references simplify this to about 10 years as the standard life span. Higher numbers such as 20 or 40 years overstate typical longevity, while lower numbers such as 2 or 5 years underestimate it severely. Thus, 10 years is the best approximate figure to represent the normal life span of an emu.

Step-by-Step Solution:
Step 1: Recall that emus are hardy birds that can survive for more than a few years in the wild or on farms.Step 2: Recognise from common references that emus typically live around a decade or a bit more.Step 3: Compare the options: 2 and 5 years are clearly too short, while 40 years is unrealistically long for an emu.Step 4: 20 years represents an upper extreme rather than a usual life span in most sources.Step 5: Therefore, 10 years is the most reasonable standard answer for the approximate life span of emus.

Verification / Alternative check:
Introductory animal husbandry texts and general encyclopaedias often state that emus live around 10 to 15 years, with some individuals possibly reaching slightly higher ages. In quiz style fact lists, this is usually rounded to about 10 years. When cross checked against such references, 10 years emerges as the best approximate value for typical life span, confirming the choice.

Why Other Options Are Wrong:
Option A: 5 years is too short for a large bird like the emu and does not match normal longevity figures.Option C: 20 years overestimates typical life span and represents an uncommon upper extreme rather than an average.Option D: 40 years is far beyond any realistic life span for emus and is clearly incorrect.Option E: 2 years is much too low and would indicate premature mortality.

Common Pitfalls:
Some learners may guess by comparing emus with smaller birds and choose a short life span, while others may confuse them with parrots or tortoises that are much longer lived. To avoid such errors, remember that emus are large birds with moderate longevity, typically living around a decade in the wild or on farms.

Final Answer:
The correct answer is 10 years.