To destroy animals and plants when they die, preventing them from fossilizing.

Decomposers

Explanation:

Decomposers are defined as those organisms that decomposes the organic components of the dead organisms. For example, microbes and saprophytes.

When plants and animals dies, the decomposers eats up the organic substance. These consumption of organic substances helps in the growth and expansion of the microbes.

The decomposers does not allow the organisms to undergo fossilization process. It prevents them from turning into a fossil. The organism completely decays if there is no hard parts present in it.

answer: option (b) is the correct answer.

explanation:

a covalent bond is formed by sharing of electrons. whereas polarity arises due to difference in electronegativity of two atoms.

therefore, more is the electronegativity of an atom which combines with the titanium, more readily it will induce a partial positive and negative charge.

thus, out of the given options fluorine is most electronegative and has an incomplete octet. therefore, it will readily combine with titanium to share the electrons and complete its octet.  

i believe you are right for all except the 3rd ( look at sqdancefan his answer is much better)