Agroup of cells working together to preform a specific job is called

Tissue

Explanation: A group of cells doing the same job forms a tissue. A group of tissues working together forms an organ. and a group of organs doing the same job is called a system.  There are 11 major organ systems in the human body.

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igneous rock formed from below the surface would have more crystals because

answer: because magma cools more slowly than lava