To cut this short and for your understanding, ionic bond is formed between metals (mostly right column in periodic table). Covalent bond is formed between non-metals (mostly left column in periodic table). So polar covalent is also a covalent bond but it is polar, which means the shape of molecules are not symmetrical hence maybe an atom in a molecule has most of the electron attracted to it causing itself to be partial negative (since electron are negatively charged) and the other atom has its electron being attracted by others became partial positive. Polar covalent can also be when H atom is binding either to F, O or N (also known as hydrogen bond).
Answer: There is no list in your question. But the three factors in which natural selection occurs are:
1. A struggle for existence,
2. Variation and
3. Inheritance
Explanation:
Darwin’s theory of natural selection is the way in which organisms change overtime.
These changes allow organisms to become better adapted to their environment and increase their chances for survival.
The three major factors through which natural selection occurs are:
1. A struggle for existence,
2. Variation and
3. Inheritance
Darwin’s theory of natural selection will occur if the three conditions above are met and unless these factors are in place, natural selection will not occur.
Mary thinking her astrological sign, Leo, is a perfect fit for her personality is a belief in pseudoscience because there is not scientific evidence confirming such beliefs.
The answer is the second option.