1) Well, you need to logically think about which of the pecan trees would be better. Tree 3 may have more clusters but they taste bitter so this is out of the option. So Tree 4 and Tree 1 would be best because they both have rich and buttery tastes and they both have a lot of clusters.
2) Not quite sure about this one, sorry :(
Complex compounds are broken down to simpler substances in catabolic reactions.
These kinds of reactions often occur in biological systems. In living organisms, complex compounds like lipids, proteins and complex sugar like cellulose are broken down into simpler forms. Products of these reactions are simple sugars, amino acids etc. but a certain amount of energy is also produced and stored in energy molecules for future use.
Oxygen and Hydrogen would most likely form a covalent bond that is polar, or a polar covalent bond. Due to the electronegativity difference between the 2 elements, unequal sharing of the valence electrons will occur, electrons being in closer proximity to Oxygen and farther away from Hydrogen. Resulting in the characteristic partial positive and negative charges to appear for the respective elements.