Final answer:
The statement about the formation of sedimentary rocks at the bottom of ancient seas is true. The Rocky Mountains were formed at a convergent plate boundary, but it was the Farallon Plate that subducted under the North American Plate, not the other way around. Folding and bending of sedimentary rocks indeed complicates relative dating.
Step-by-step explanation:
To assess the statements provided about tectonic plates and sedimentary rock, we must look into geological evidence and principles. First, considering tectonic plate movement, when two plates converge, the denser plate typically subducts underneath the less dense plate. In the case of the North American and Farallon plates, it was the Farallon Plate that subducted beneath the North American Plate, contrary to the statement given. Metamorphic and sedimentary rocks that form at the bottom of ancient seas, as indicated in one of the statements, indeed record the conditions of past environments. Lastly, when sedimentary rocks bend and fold due to tectonic forces, such as at convergent plate boundaries, it can indeed make relative dating challenging because the original layering of the rocks is disturbed.
The statement regarding Rocks formed at the bottom of ancient seas being sedimentary is true. The statement that the Rocky Mountains were formed at a convergent plate boundary is also true, as they are a result of the subduction process involving the Farallon Plate and the North American Plate. However, the statement that the North American Plate subducted under the Farallon Plate is incorrect, as the Farallon Plate was the one that actually subducted. Regarding the relative dating of sedimentary rocks, it can become difficult when these rocks bend and fold, as geological processes such as folding can disrupt the original sequencing of layers, hence complicating the determination of their chronological order.