Limits to variation The most obvious limit to natural selection is that suitable variation may not be available. This may be because certain phenotypes cannot be built, being ruled out either by physical law or by the properties of biological materials.
Answer:
maintaning the essential internal parameters relatively constant is the phrase that best describes the process of homeostasis.
Answer:
Non-use of drugs:
1. A teen is with family and friends.
2. A teen is a healthy student and athlete
3. A teen is focused and living life free and happy.
Use of drugs:
1. A teen doesn't socialize and doesn't around too many people due to social anxiety caused by the use of drugs.
2. A teen has health problems in his liver and kidney due to the abuse of drugs and is not able to play any sports due to this permanent health condition.
3. A teen is in jail due to being caught in possession of drugs and failing a drug test and being unhappy with anxiety and addiction.