• If both the medium and cell has exactly the same water concentration and thus, there will be no net movement of water across the cell membrane is known as an isotonic solution. 
• The cells remain of the same size.
  
  Hence, the correct option is B.

Hypotonic solution is a type of solution in which water concentration in the medium is more than the cell. Water crosses the membrane in both directions, but more water will come into the cell than will leave. The net result is that the water enters the cell. The cells will swell up. 

A hypertonic solution is a particular type of solution that has a greater concentration of solutes on the outside of a cell when compared with the inside of a cell. Water crosses the cell membrane in both directions, but more water leaves the cell than enters it. Therefore, the cell will shrink due to exosmosis.

A hypotonic environment is when the solute concentration outside the cell is less than inside the cell.

Osmosis happens along a concentration gradient. If outside medium is hypotonic, it means that relatively more of water is present outside the cells in the surrounding medium and water will flow inside the root hair cells.

Howard and Pelc divided cell cycle in four stage. The cell cycle is an ordered set of events, culminating in cell growth and division into two daughter cells. Non-dividing cells not considered to be in the cell cycle. The stages  are G$ _1$-S-G$ _2$-M. The G$ _1$ stage stands for "GAP 1". The S stage stands for "Synthesis". This is the stage when DNA replication occurs. The G$ _2$ stage stands for "GAP 2". The M stage stands for "mitosis", and is when and cytoplasmic division occur.

Sphaerosomes are single half unit membrane covered small spherical organelles which synthesize and store fats. The cell wall of bacteria is made up of glycocalyx (carbohydrate and amino acids). Chloroplasts are eukaryotic plant cell organelles which have an internal thylakoid membrane system. The thylakoid membranes carry out the light reactions part of photosynthesis. The chromosomes of a eukaryotic cells are called its karyotype. The diagrammatic representation of a cells karyotype is called an idiogram.

Cell wall was discovered by Robert Hooke, in 1665, when he saw an empty box like compartments in a very thin slice of cork under his microscope. He wrote a book Micrographia and coined the term Cellula which was later on changed into cells. Robert Hooke thought cells to be passages for conducting fluids. Actually, he had observed compartments made up of the cell wall and not true living cells.

RBC (red blood cell) of the human is the best material for the study of structure of cell membrane. Chemical studies on the RBC cell membrane enabled the scientists to infer the possible structure of plasma membrane.