Final answer:
The statement that discrete models are more common and easily understood is false, as understanding depends on individual backgrounds. In science, models and theories have limited validity while laws are generally considered universally valid.
Step-by-step explanation:
The statement "Discrete models are more common and more readily understood by persons of varied backgrounds" is False. A discrete model represents a system with countable states or elements; it is not ubiquitously easy to understand as it depends on the specific background and education of individuals. Even though discrete models are used widely in various fields such as computer science and mathematics, the level of commonality and ease of understanding varies.
Models, theories, and laws in science have different levels of certainty and applicability. Models and theories have limited validity as they may not apply in every scenario and can be modified or rejected based on new evidence. However, laws are generally considered to be universally valid as they have been repeatedly tested and widely accepted. Therefore, answer d is correct: models and theories have limited validity while laws are universally valid.