So abiotic means nonliving, so the only abiotic option is B. the gravel on the bottom of the aquarium.
A) a common ancestor
Homologous structures are structures that are similar in related organisms. There is a basic pattern of bones which can be inherited from a common ancestor
Guard cells. They open and close to allow for gas exchange within the leaf
Explanation:
Carrying capacity is determined by limiting factors.
Carrying capacity is determined by limiting factors which affect the amount of resources available. Limiting factors may include water, space, nutrients, minerals, light, etc.If we're discussing carrying capacity in the context of a species, the number of available mates, predation, disease, or competition with another species could determine the species' carrying capacity. For example, a species of bird may have plenty of space and but if it needs to compete with another species for food, the degree and extent of competition will limit the population.
Or there may be plenty of available habitat, food, and water for tigers in India, but if there are only a few tigers breeding and producing offspring, the carrying capacity of the species will be determined by the number of females producing young.
Many of these same limiting factors apply when we refer to the carrying capacity of an ecosystem. For example, in a desert ecosystem, there may be plenty of available space, but the number of organisms the system can hold may depend on the amount of water.
Another ecosystem may be limited by nutrient-poor soil. If the soil in an area is low in nutrients, fewer photosynthetic plants will be able to grow, which means less food for organisms consuming the plants, which means less food for organisms that eat those organisms, and so forth. The nutrient concentration of the soil affects the carrying capacity of the entire ecosystem.
This hormone is known to regulate blood pressure.
