Explain what would happen to a red blood cell placed in a solution of 99.3 percent water and 0.7 percent salt.

and

how can a small particle or liquid droplet enter a cell?

i don't know am stupid

When a red blood cell is placed in a solution with a higher concentration of water (99.3 percent) and a lower concentration of salt (0.7 percent), a process called osmosis occurs. Osmosis is the movement of water molecules across a semipermeable membrane from an area of lower solute concentration (in this case, the red blood cell) to an area of higher solute concentration (the solution).

In this scenario, the red blood cell has a higher solute concentration (solute being the salt dissolved in the cell) than the external solution. As a result, water molecules from the solution will move across the cell membrane to achieve equilibrium, or balance of solute concentration. This is because water naturally moves towards areas with a higher solute concentration.

As water enters the cell, it will cause the red blood cell to swell and expand. If the influx of water is substantial, the cell may eventually burst or undergo lysis, leading to the cell's destruction. This process is known as hemolysis.

To summarize, when a red blood cell is placed in a solution with a higher concentration of water and a lower concentration of salt, water will move into the cell through osmosis, causing the cell to swell and potentially burst.

As for your second question, small particles or liquid droplets can enter a cell through different mechanisms depending on their size and properties. Here are a few common ways:

1. Diffusion: If the particle or droplet is small enough and lipid-soluble, it can passively diffuse across the cell membrane. This occurs by moving from an area of higher concentration to an area of lower concentration until equilibrium is reached.

2. Endocytosis: Large particles or droplets can enter the cell through a process called endocytosis. This involves the cell membrane engulfing the particle or droplet, forming a vesicle around it. There are different types of endocytosis, such as phagocytosis (cell engulfing solid particles) and pinocytosis (cell engulfing liquid droplets).

3. Transport proteins: Some particles or droplets can enter the cell with the help of specific transport proteins embedded in the cell membrane. These proteins facilitate the movement of specific substances across the membrane, either by active transport (against the concentration gradient) or facilitated diffusion (along the concentration gradient).

It's important to note that the ability of particles or droplets to enter a cell depends on their size, solubility, charge, and the presence of specific receptors in the cell membrane. These factors determine the most suitable mechanism for their entry.