Why are chloroplasts found only in plant cells?

Chloroplasts are found exclusively in plant cells (and some protists) because:

• Energy source: Plants are autotrophs that produce their own food through photosynthesis, which requires chloroplasts
• Survival strategy: Unlike animals that obtain energy by consuming other organisms, plants must manufacture glucose using sunlight
• Evolutionary adaptation: Plants evolved chloroplasts to convert light energy into chemical energy
• Stationary lifestyle: Since plants cannot move to find food, they developed the ability to make food using sunlight, water, and carbon dioxide

Animals are heterotrophs that obtain ready-made organic nutrients by eating plants or other animals, so they have no need for chloroplasts or the photosynthesis process. Instead, animals have mitochondria to extract energy from the food they consume.