The 90 degree East Ridge, an important submarine feature, is located in which one of the following oceans?

Introduction / Context:
Ocean floors are not flat; they contain ridges, trenches, plateaus and other submarine features. Some of these features are important markers in oceanography and are frequently mentioned in geography exams. The 90 degree East Ridge is one such feature, and this question checks whether you know in which ocean it lies.

Given Data / Assumptions:

• The submarine feature mentioned is the 90 degree East Ridge.
• The four options are the Pacific, Atlantic, Indian and Arctic Oceans.
• We assume the standard classification of submarine ridges as described in school and college geography texts.

Concept / Approach:
The 90 degree East Ridge is a long, north south trending submarine ridge lying in the eastern part of the Indian Ocean. Its name comes from its approximate alignment near the 90 degree east meridian of longitude. It runs parallel to the Ninety East meridian and is an important structural feature of the Indian Ocean floor. Therefore, when asked which ocean it lies in, the correct answer is the Indian Ocean.

Step-by-Step Solution:
Step 1: Recall that the term 90 degree East refers to longitude, which passes through the eastern Indian Ocean region.Step 2: Remember that many geography references describe the 90 degree East Ridge as a prominent submarine ridge in the Indian Ocean.Step 3: Compare this with the main mid ocean ridge systems in the Pacific and Atlantic Oceans, which have different names and positions.Step 4: Note that the Arctic Ocean does not feature prominently in standard exam questions about the 90 degree East Ridge.Step 5: Conclude that the correct ocean is the Indian Ocean.

Verification / Alternative check:
Ocean floor maps in atlases usually show the 90 degree East Ridge near the central and eastern Indian Ocean, running roughly parallel to the Ninety East longitude. It is often mentioned together with other Indian Ocean features such as the Carlsberg Ridge and the Central Indian Ridge. No similar label appears in the Atlantic, Pacific or Arctic maps, confirming that the ridge in question belongs to the Indian Ocean basin.

Why Other Options Are Wrong:
Pacific Ocean: Contains its own system of mid ocean ridges and trenches, but the specific 90 degree East Ridge is not located there.Atlantic Ocean: The main ridge here is the Mid Atlantic Ridge, a different feature from the 90 degree East Ridge.Arctic Ocean: A smaller and more enclosed ocean with its own submarine features, but not the one mentioned in this question.

Common Pitfalls:
A common error is to guess the Pacific Ocean simply because it is the largest and has many ridges. Others might be unsure of the name and choose randomly. The best way to avoid mistakes is to remember the simple link between 90 degree East and the Indian Ocean and to revise major ocean floor features by ocean basin. Once this association is clear, questions like this become straightforward.

Final Answer:
The 90 degree East Ridge is located in the Indian Ocean.