21. on first attachment is secondary succession
22. is the degree of variation of life....
genetic, species or ecosystem within a specific area, system or planet
23. the last one is wrong = )
Answer:
Explanation:
In cellular biology, active transport is the movement of molecules across a membrane from a region of lower concentration to a region of higher concentration—against the concentration gradient. Active transport requires cellular energy to achieve this movement.
The genes in a population give forth the genetic variability across a population (genotypes). In addition, occasional mutations of these genes in a population increase this genetic variability. Hovever, natural selection only favours reproduction of individuals with genes that are favourable in the environment/habitat. Therefore, natural selection has no foresight but is rather pegged on being an ‘opportunistic’ process.
Answer:
the last food chain is the last predator of the enature food chain which ends that particular food chain and inturn the circle of life
