Machine learning is characterized by what key feature?

The key feature of machine learning is its ability to improve performance through experience. This means that as a machine learning model is exposed to more data over time, it can learn patterns and make more accurate predictions or decisions without being explicitly programmed for every specific task. The learning process involves adjusting its parameters based on the data it encounters, which enables the model to adapt and enhance its performance based on the training it receives.

In contrast, other options do not reflect the core principles of machine learning. For instance, using manual coding for every task suggests a traditional programming approach where each scenario must be individually coded, which contrasts with machine learning's focus on data-driven learning. Reliance on fixed algorithms without changes overlooks the dynamic nature of machine learning, where algorithms are tweaked based on new data and experiences. Finally, the idea of eliminating the need for data collection is fundamentally misaligned with machine learning, as data is the cornerstone upon which models learn and improve. Hence, the correct answer highlights the essence of learning and adaptation that defines machine learning.