Which landform represents the boundary between the land and an ocan or lake a) coastline b) delta c) dune d) glacier

First of all, a coast is where land ends and the sea/lake starts.

Therefore, the coastline, is the "border", or as you said it, the boundary between the continent and a sea or in some cases a lake.

Hope it helped,

BioTeacher101

science-ocean floors and habitats study guide by volleyballqueen3817 a major advance in ocean-floor mapping. list four sections of the ocean floor. algae that use sunlight to produce their own food through photosynthesis. all of the feeding relationships that exist in a habitat. drying out, predators, find food.