Your Answer : (Not Answered)

Correct Answer : A

They are the high field strength elements (HFSE).

HFSE such as Zr, Hf, Nb, Ta and Ti form small ions with high charge (+3 to +5 and more), so their ratio of charge to radius, the field strength, is high. Their charge is too great for the octahedral sites occupied by Mg²⁺, Fe²⁺ and Ca²⁺, and they are too big for the tetrahedral sites of Si and Al, so they behave as incompatible elements.

Large ion lithophile elements (K, Rb, Cs, Sr, Ba) are incompatible for the opposite reason: large ions with low charge. Transition metals such as Ni and Cr fit readily into octahedral sites, and heavy rare earth elements are a separate group defined by atomic number.

Your Answer : (Not Answered)

Correct Answer : B

The correct order is diagenesis - catagenesis - metagenesis.

In diagenesis, at shallow depth and low temperature, organic matter is altered by bacteria and chemical reactions into kerogen, with some biogenic methane. In catagenesis, at greater depth and about 50-150°C, kerogen is thermally cracked to oil and then wet gas: this is the oil window. In metagenesis, at still higher temperature, the remaining material yields only dry gas (methane) and residual carbon.

The other orders put catagenesis or metagenesis first, which is impossible, since kerogen must form in diagenesis before it can be cracked to hydrocarbons.

Your Answer : (Not Answered)

Correct Answer : B

The missing component is lipid.

Marine plankton and algae are rich in lipids (fats, oils and waxes), which are long hydrocarbon chains with very little oxygen. That hydrogen-rich, oxygen-poor organic matter is what generates oil, whereas land plants are dominated by carbohydrates such as cellulose, built of C₆H₁₀O₅ units with one oxygen for every carbon or so, which tend to form coal and gas.

Fulvic acids are soil humic substances and amino acids are the building blocks of proteins; neither explains the low oxygen content of petroleum. 'Pepofine' is not a recognised constituent.