Cell Membrane. Even cells with cell walls have a membrane
Answer:
D) Communities
Explanation:
Communities are groups of biotic living beings in an ecosystem such as animals, plants , bacteria, etc whereas populations are just groups of creatures of the same species. Multiple different populations make up a community.
It travels through the more dense medium until it reaches the boundary with a less dense medium. MIDDLE: At the boundary, both reflection and transmission occur. ... The reflected pulse becomes inverted when a wave in a less dense rope is heading towards a boundary with a more dense rope.
Humans live in the layer of the atmosphere referred to as the troposphere. (Most of the mass of the atmosphere can be found in the troposphere.)
