The perspective matters. Tungsten boasts the highest melting point among metals and superior crack resistance compared to titanium. It is also exceptionally resistant to corrosion and wear. making it a top choice for producing equipment and instruments that endure harsh environments. Conversely. titanium offers an impressive strength-to-weight ratio. rendering it suitable for scenarios where both strength and weight are crucial. such as in the aerospace sector. Moreover. it displays remarkable corrosion resistance. Ultimately. the superiority of tungsten or titanium will hinge on the specific demands of the task at hand.

Polypropylene, a popular thermoplastic polymer, is not intrinsically stretchy in its standard form. It is known for its stiffness, excellent chemical resistance, and high melting point, making it ideal for rigid packaging, automotive parts, and textiles. However, its lack of elasticity can be modified in certain applications. For instance, when polypropylene fibers are manufactured into fabrics, they can be woven or treated in ways that impart some degree of stretchiness, often through the incorporation of elastomeric materials or specific textile processing techniques. Despite these modifications, polypropylene's natural flexibility and stretchability remain relatively low compared to inherently stretchy materials such as spandex or natural rubber.

Under typical conditions. calcium carbonate and titanium dioxide are stable solids that do not react with each other. While titanium dioxide is usually chemically inert at high temperatures or in the absence of strong acids or bases. there may be instances when reactions occur. particularly when other compounds are present. These reactions can lead to the formation of various compounds. but the specific results are highly dependent on the conditions at hand. In certain industrial processes. for example. TiO2 may combine with CaCO3 at elevated temperatures to produce calcium titanate CaTiO3. However. this is a complex reaction and must be carried out under very specific circumstances. It is strongly advised to conduct this reaction in a controlled environment and seek specialized assistance if uncertain about the outcome.