Which of the following best describes 'sensitivity' as a characteristic of animals?

The correct choice highlights 'sensitivity' as the animal's ability to respond to stimuli in their environment. This characteristic is fundamental for survival, as it enables animals to detect changes in their surroundings, such as the presence of predators, prey, or changes in temperature. Sensitivity can manifest through various sensory modalities, including sight, sound, touch, taste, and smell, allowing animals to react appropriately to different situations, which is crucial for their adaptation and survival.

In contrast, movement pertains to an animal's locomotion and does not specifically denote responsiveness to environmental cues. Growth and development involve the changes an organism undergoes from birth to adulthood, which is a separate characteristic from immediate responsiveness to external factors. Finally, the process of nutrition acquisition relates to how animals obtain energy and nutrients, which, while essential for survival, is not directly associated with the concept of sensitivity. Thus, the emphasis on responsiveness aligns perfectly with the definition of sensitivity in animals.