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

1. loamy sand is about 80% sand with 10% clay and defined mostly by sand particles with some clay to provide structure and fertility. the sand particles are easily visible and the soil holds structure but breaks apart easily.

2. scott sand can improve his soil quality by incorporating more silt and organic matter into the soil. peat moss and organic matter can also be incorporated.