In zoological classification, Equus asinus is the scientific name of which common domestic animal?

Introduction / Context:
Scientific names follow a standard system called binomial nomenclature. This system uses a two part Latin name to uniquely identify every species on Earth. Many general knowledge and biology questions ask you to match a scientific name to its common name. In this question, the name Equus asinus is given and you are asked to identify the corresponding common domestic animal. Understanding such names improves clarity in scientific communication and avoids confusion caused by regional common names.

Given Data / Assumptions:

- The scientific name given is Equus asinus.
- The options list four common animals: donkey, cow, deer and kangaroo.
- We assume standard zoological nomenclature is followed as used in school and competitive exam biology.
- Only one option correctly corresponds to Equus asinus.

Concept / Approach:
Binomial nomenclature uses a genus name followed by a species name. Both parts together make the full scientific name. Animals in the same genus share the first word but differ in the second. In this case, Equus is the genus that includes horse like animals such as the horse, donkey and zebra. The second part asinus points to a specific species within the genus Equus. By recalling which animal is classified as Equus asinus, we can select the correct option from the list.

Step-by-Step Solution:
Step 1: Note that the genus Equus includes horse like mammals such as horses, donkeys and zebras.Step 2: Remember that the domestic horse is classified as Equus caballus, so Equus asinus must refer to a different species within the same genus.Step 3: Among the given options, the donkey is the well known close relative of the horse, and it belongs to the same general group of equine animals.Step 4: Standard biology references identify the domestic donkey as Equus asinus.Step 5: Therefore, the correct answer is donkey.

Verification / Alternative check:
A quick verification method is to recall a few common scientific names that are often repeated in textbooks. Equus caballus is the horse, Equus zebra is the zebra and Equus asinus is the donkey. If you can recall at least one of these correctly, you can confidently match Equus asinus with the donkey. Another check is that cows, deer and kangaroos belong to very different mammalian groups with different genera, not to the genus Equus.

Why Other Options Are Wrong:
Option Cow: Domestic cattle are classified under the genus Bos, with the common domestic cow referred to as Bos taurus, so this does not match Equus asinus.
Option Deer: Deer belong to various genera such as Cervus or Axis and not to the genus Equus, so they cannot have the name Equus asinus.
Option Kangaroo: Kangaroos are marsupials and belong to the genus Macropus or closely related genera, which is entirely different from Equus.

Common Pitfalls:
Many learners confuse scientific names because they focus only on the second word or only on the general type of animal. Some might guess cow or deer simply as familiar animals without remembering the correct genus. Another mistake is assuming that any common domestic animal can match any Latin name without recalling the genus structure. Revising a small list of high frequency scientific names used in exams greatly reduces such confusion.

Final Answer:
The correct answer is Donkey.