Verbal Reasoning - Same Meaning 3

'To flag' = 'to falter'; there is no immediate overlap with the idea of a flag to be planted at the summit as a visible symbol of the mountaineers' achievement

To 'resist' = to try as hard as one can to prevent (or at least slow down) something.
There is also a specialist meaning in the field of electrical engineering (Answer 1) but that is unlikely to be a major issue in such a situation as this

'Harmoniously' means 'in ways that agree with each other' or 'on the same wavelength', but not necessarily with music going on all the time (though that may also happen to be true). There is no connection whatever with 'harm' (as Answer 4 might have appeared to you to suggest)

An 'heirloom' is any inherited item: it could just as well be a picture, ornament or piece of furniture. The '-loom' element in the word does not necessarily imply any connection with threads or weaving, though in the case of a spinning-wheel it may have been tempting to assume so

'Wholesome' = 'natural (though not necessarily organic), balanced, good for you'. There is no link at all with 'holes' (in a diet with some things forbidden, as suggested by Answer 3) nor holes in the cheese.
(Meanwhile we have heard it claimed that if ever you look at cheese under a microscope, you may be unlikely to eat any again; but we suspect you are unlikely to wish, nor have the apparatus, to try this!)

Most of these Answers seem likely and tempting, but No.3 is the best: anything 'spindly' consists of parts, including perhaps any structural supports, that look too thin to be able to sustain their load (perhaps like the legs of a 'daddy-long-legs')

This is similar to when your skin (on your lips, perhaps) becomes chapped from the cold, or maybe you have a rough place where something you have been wearing or carrying has rubbed against it repeatedly. Leather, of course, would once have been the skin of a living animal!

'Lumber' in its original sense is a quantity of chopped-down trees, on their way to be processed into paper or furniture or whatever (e.g. by 'lumberjacks' floating rafts down a river, at least in the initial stages). 'Lumbered with' suggests having a load of something awkward dumped on one; in this case, tiresome non-related children. There is no connection with 'slumber' (as Answer 1 may have seemed to hint); nor, necessarily, that all the children will collectively be expected to do housework (Answer 4)

The forest may well be shady, but at the distance of the horizon we couldn't be able to tell this clearly, and in any case the landscape is under at least partial cloud rather than glaring sunshine. 'Shading' in this sense means 'blending or harmonizing subtly, so it is hard or even impossible to tell quite where one area ends and another begins'.
This would presumably involve clever selection of subtle colors, but there is no suggestion that the artist has actually confused (Answer 4) part of the ground-based landscape with something in the sky

'Flat' (in this somewhat technical sense) means 'below the correct pitch'. It's unlikely that the person singing is physically flat or even just horizontal (though they might be); there is no suggestion of them being in a separate 'flat' ( = apartment; as in Answer 4), either