For the first question:
Valuable ore deposits and gem crystals are often associated
with igneous intrusions. So for this question the correct option is option “d”.
An example like the Pegmatite’s, which are a form of igneous intrusions, is
responsible for the creation of variety of gems like topaz and tourmaline.
For the second question:
For this specific question, option “c” seems to be the
correct option. Weathering, deposition, compaction, cementation are the
possible sequence that leads to the formation of sedimentary rocks.
The role<span> of a </span>decomposer<span> is to decompose or break down dead matter in the environment. Plants make their own food by the process of photosynthesis and also produce (hence the name) food for other </span>consumers<span>. Without </span>producers<span> an </span>ecosystem<span> could not sustain itself.</span>
D
Sharing
Formation of water is a covalent bond which involves the sharing of electrons between two reacting atoms so that both can attain the stable octet structure
