Dispersal is the movement of an individual away from its birthplace to breed or establish somewhere else. This differs from migration, which is a seasonal, directed move between habitats often tied to breeding or resource changes and may recur each year. It also isn’t staying in the natal area to raise offspring, which is natal philopatry or remaining in the birthplace. The purpose of dispersal is to reduce competition and inbreeding and to allow gene flow and potential colonization of new areas, which is why this definition best captures the idea of relocating to reproduce elsewhere.

Photosynthesis is how some organisms turn light energy into food, producing sugars from carbon dioxide and water. Plants do this, and they are multicellular organisms with rigid cell walls made of cellulose that give them structure. Fungi also have cell walls, but they don’t photosynthesize; they obtain nutrients by absorbing them from their surroundings. Animals, including monotremes, don’t have cell walls and don’t perform photosynthesis. So the combination of using light to make food, being multicellular, and having cellulose cell walls points to plants.

Energy flow in ecosystems starts with producers, the organisms that capture energy and convert it into usable chemical energy. In most mammal ecosystems, producers are autotrophs like plants or algae that use sunlight to build organic molecules. Primary consumers then obtain energy by eating these producers, and secondary or tertiary consumers obtain energy by eating those primary consumers. Decomposers play a crucial role too, breaking down dead matter and recycling nutrients, but they aren’t the primary link in the energy-transfer chain. So, the best way to describe the basic trophic level order is that producers synthesize energy from inorganic sources; primary consumers eat producers; secondary/tertiary consumers eat primary consumers.

Diurnal mammals are active during daylight hours. This daily pattern means they do most of their foraging, socializing, and activities when the sun is up and rest at night, guided by their circadian rhythms. The other statements describe different patterns: being active at night points to nocturnal species, being active during twilight points to crepuscular species, and hibernation describes seasonal dormancy rather than a daily time-of-day activity pattern. So the statement that they are active during daylight hours best fits what defines diurnal mammals.