1. All of the mentioned
2. It is an application-specific integrated circuit, to accelerate the AI calculations and algorithm.
3. The Tensor Processing Unit (TPU) is a custom ASIC chip—designed from the ground up by Google for machine learning workloads—that powers several of Google's major products including Translate, Photos, Search Assistant and Gmail.
4. Tensor Processing Unit is an AI accelerator application-specific integrated circuit developed by Google specifically for neural network machine learning.

Tensor Processing Unit is an AI accelerator application-specific integrated circuit developed by Google specifically for neural network machine learning, particularly using Google's own TensorFlow software.