Answer:
The relationship between environment, variation and selection lay the foundation for natural selection and evolution.
Genetic variations are present among species due to number of reasons like recombination or crossing over during meiosis, mutations, random fertilization etc. These factors bring changes among the members of a species. Some of the species become better adapted to survive in a particular environment whereas some are not better adapted and become extinct over a period of time. The environment selects the organisms that are best adapted to survive and hence lead to variations.
Answer:
A cutaneous membrane is a multi-layered membrane composed of epithelial and connective tissues. The apical surface of this membrane exposed to the external environment and is covered with dead, keratinized cells that help protect the body from desiccation and pathogens....
Genetic exchange between two homologous chromosomes is called cross over
Vacuoles are storage bubbles found in cells. They are very large in plant cells and are used to store a variety of nutrients a cell might need to survive.
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) Sea Floor Spreading <span>a process by which molten material erupts at mid-ocean ridges and is split and spread by later erupting molten material</span>
