In scientific terminology, a specialist who studies water in all its forms, movement and distribution on Earth is called what?

Introduction / Context:
Water is a fundamental natural resource that supports ecosystems, agriculture, industry and human life. The scientific study of water, including its distribution, movement, quality and interaction with land and the atmosphere, is a recognised discipline. General knowledge and environmental science questions often test whether students know the correct term for a scientist who specialises in this field, differentiating it from other branches of science with similar sounding names.

Given Data / Assumptions:

The question asks for the correct professional term for a scientist who studies water.
The options include geographer, herpetologist, archeologist and hydrologist.
We assume the focus is on water in rivers, groundwater, rainfall and related systems, not only on ocean water or marine biology.
The task is to match each term to its usual scientific meaning and select the one that corresponds to water study.

Concept / Approach:
The key concept is that hydrology is the science of water, especially its occurrence, circulation and distribution on and below the Earth's surface and in the atmosphere. A person who works in this field is called a hydrologist. By contrast, a geographer studies the Earth's landscapes, environments and human spatial relationships more broadly, a herpetologist studies reptiles and amphibians, and an archeologist studies human history and prehistory through material remains. Understanding each term allows us to eliminate the incorrect options and choose the right one.

Step-by-Step Solution:
Step 1: Examine the word hydrologist and recognise the prefix hydro, which is commonly associated with water in terms like hydropower and hydrosphere. Step 2: Recall that hydrology focuses on the water cycle, including rainfall, rivers, groundwater and evaporation, making hydrologist the specialist in water studies. Step 3: Consider the term geographer, which covers a wide range of topics such as landforms, climate, population and economic activities, not exclusively water. Step 4: Identify herpetologist as a scientist who studies reptiles and amphibians like snakes, lizards and frogs, again not directly tied to water science. Step 5: Recognise archeologist as someone who studies ancient cultures through excavation of artefacts, which is unrelated to the physical science of water. Thus, the only correct term for a scientist who studies water is hydrologist.

Verification / Alternative check:
Textbooks in geography and environmental science define hydrology as the scientific study of the movement, distribution and quality of water on Earth. Professional organisations and university departments that deal with water resources management, flood forecasting and watershed studies also use the term hydrologist for experts in this field. This consistent terminology across academic and practical contexts confirms that hydrologist is the accepted term, whereas the other options belong to different scientific specialties.

Why Other Options Are Wrong:
Geographers may examine rivers, lakes and oceans as part of broader spatial studies, but their discipline is not restricted to water alone, so the term geographer is less precise than hydrologist for this question. Herpetologists focus on a group of animals and may sometimes work in aquatic habitats, but their main subject is reptiles and amphibians, not water itself. Archeologists investigate human past through material remains and only incidentally deal with water related questions such as ancient irrigation. None of these titles describes a scientist whose primary focus is water.

Common Pitfalls:
Some students may choose geographer because they have learned about rivers and oceans in geography classes and therefore associate the subject with water. Others may be misled by the similarity between words like hydrologist and other scientific terms if they have not encountered them often. To avoid these errors, it helps to link the prefix hydro with water in many contexts and remember that hydrology is the dedicated science of water resources.

Final Answer:
A scientist who studies water, including its distribution and movement on Earth, is called a hydrologist.