The lagging strand template of a dna molecule undergoing replication reads 3'-cgcatgtagcga-5'. what is the sequence of the dna that is the template for the complementary leading strand of this segment?

The principle is that adenine is always paired to thymine; and cytosine is always paired to guanine. In this particular sequence:

3'-cgcatgtagcga-5'

The complementary leading strand will be:

5'-GCGTACATCGCT-3'

Although i don't know what is the simulated system, starfish are predators that eat mostly  microalgae,  snails, sponges, bivalves, mussels and other small marine animals. removing starfish from any system would definitely increase this animals that they prey.