In world geography, which water body is recognised as the largest lake in the world by surface area?

Introduction / Context:
This question tests knowledge of physical geography, particularly large inland water bodies. Although it is named a sea, the Caspian Sea is technically a landlocked water body and is widely classified as the largest lake in the world by surface area. Competitive exams often ask candidates to identify this fact among other well known large lakes such as Superior, Baikal and Victoria. Understanding the distinction between seas that are open to oceans and enclosed seas like the Caspian is important for correct classification in geography questions.

Given Data / Assumptions:

• The focus is on the largest lake by surface area, not by volume or depth.
• Options include Caspian Sea, Lake Superior, Lake Baikal and Lake Victoria.
• Caspian Sea is treated as a lake because it is completely landlocked.
• We assume standard geographical definitions used in school and exam references.

Concept / Approach:
The key concept is that the Caspian Sea, bordered by countries such as Russia, Kazakhstan, Turkmenistan, Iran and Azerbaijan, has no natural outlet to the world oceans and is therefore classified as the worlds largest lake by area. Lake Superior is the largest of the Great Lakes of North America but is smaller in area than the Caspian. Lake Baikal in Russia holds the record for deepest and one of the largest lakes by volume, but not by surface area. Lake Victoria in Africa is also large but still does not match the Caspian. Therefore, among the given options, Caspian Sea is the correct answer when the question focuses on largest lake by surface area.

Step-by-Step Solution:
Step 1: Interpret the term largest lake as referring to surface area, since that is the usual meaning in exam oriented GK unless stated otherwise. Step 2: Recall that the Caspian Sea, although called a sea, is a fully enclosed inland water body and counted as a lake in geography. Step 3: Compare it with Lake Superior, the largest of the Great Lakes, which is still smaller in area than the Caspian Sea. Step 4: Remember that Lake Baikal is famous for great depth and volume, not for maximum surface area. Step 5: Note that Lake Victoria ranks high among freshwater lakes by area but still falls behind the Caspian Sea, leading to the conclusion that Caspian Sea is the correct answer.

Verification / Alternative check:
To verify, candidates can recall standard lists of superlatives that appear in geography notes, where Caspian Sea is explicitly labelled as the largest lake by area. In the same lists, Lake Superior may be mentioned as the largest freshwater lake by surface area, and Lake Baikal as the deepest lake. This pattern confirms that Caspian Sea is associated with the overall largest lake category and should be selected when such a question appears, provided the focus is on lakes in general and not limited to freshwater lakes only.

Why Other Options Are Wrong:
Lake Superior is the largest freshwater lake by surface area but is smaller in total area than the Caspian Sea. Lake Baikal is the deepest lake and has very large volume, but its surface area is less than that of the Caspian Sea. Lake Victoria is a major African lake with large area but does not surpass the Caspian Sea in size.

Common Pitfalls:
Students sometimes get confused by the word sea in Caspian Sea and think it should be excluded from the lake category. Others misremember related records and choose Lake Superior or Lake Baikal, mixing up surface area and volume or depth. To avoid such mistakes, it is helpful to memorise a short table: Caspian Sea largest lake by area, Lake Superior largest freshwater lake by area and Lake Baikal deepest lake by depth, and always read carefully whether the question is about all lakes or only freshwater lakes.

Final Answer:
The largest lake in the world by surface area is the Caspian Sea.