Models are simplified representations of of different complex systems. They also help to study very small or large objects.
Option B, D and E.
Explanation:
Models are very simplified representations of complex systems and organs or structures which are prepared to study those systems by scientists and normal people easily. Many structures of human body like cells or some tissues are very small in structure or microscopic in nature. So studying them are very hard without specific instruments which are not always available. Thus models are made to easily study those structures by scientists and even normal people and students.
<span>Normally sterilizing food using radiation does not induce radioactivity but sometimes it may change the taste, texture of the food and it may also destroy the nutrients. radiation is used to kill the harmful bacteria and to increase the shelf life. when the radiation is very energetic it alters the food structure but it does not make it radioactive. To become radioactive one has to make a nucleus unstable. ionizing radiation normally cannot do this. FDA has established maximum energy levels for radiation to prevent the treated foods from becoming radioactive. The energy levels of the rays are too low to induce radioactivity in the food. So there is no harm in consuming treated foods.</span>
The four postulates of the natural selection include.
1. individuals possessing particular traits are have higher likelihood of surviving and reproducing.
2. different individuals in a population have different traits
3.reproductive and survival rate vary with individuals in a given population.
4. some trait differences are inheritable.
