Answer:


In this question, we are asked to identify which of the following animals has a liquid skeleton. The options given are a fish, snake, bird, and earthworm. To determine the correct answer, we need to understand what a liquid skeleton is and how it relates to each of these animals.


A liquid skeleton, also known as a hydrostatic skeleton, is a structure found in certain animals that relies on the pressure of fluid within their body cavities to provide support and movement. It allows these animals to move and change shape without the need for a rigid skeleton made of bones or cartilage.


Let's examine each of the given options to determine which one has a liquid skeleton:

Fish: Fish have a skeleton made up of bones and cartilage, similar to most vertebrates. They do not have a hydrostatic or liquid skeleton.

Snake: Snakes also have a skeleton made up of bones and cartilage. While they are highly flexible and can bend and twist their bodies in various ways, they do not possess a liquid skeleton.

Bird: Birds, like fish and snakes, have a skeletal system composed of bones. Their bones are lightweight and hollow, which enables them to fly, but they do not have a liquid skeleton.

Earthworm: Earthworms, unlike the previous options, have a hydrostatic or liquid skeleton. Their bodies are made up of segments filled with fluid. The contraction and relaxation of muscles in these segments, along with the fluid pressure, allow earthworms to move and burrow through the soil.


Based on the information provided, it can be concluded that the animal with a liquid skeleton is the earthworm. The other options, including fish, snake, and bird, have skeletal systems composed of bones and cartilage rather than a hydrostatic or liquid skeleton.

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