Absorption of digested food is carried out by -

Options

A. Passive method
B. Active transport
C. Facilitated transport
D. All

Answer

**Step-by-Step Solution:**

1. **Understanding Absorption**: The absorption of digested food occurs primarily in the small intestine, where nutrients from the food are transferred into the bloodstream.

2. **Types of Transport Mechanisms**: There are three main transport mechanisms involved in the absorption of digested food:
- **Passive Transport**: This process does not require energy. Nutrients move from an area of higher concentration to an area of lower concentration. An example of this is the diffusion of simple sugars and amino acids.

- **Facilitated Transport**: This type of transport also does not require energy but involves specific carrier proteins that help move substances across cell membranes. This is important for larger or polar molecules that cannot easily pass through the lipid bilayer.

- **Active Transport**: Unlike passive and facilitated transport, active transport requires energy (in the form of ATP) to move substances against their concentration gradient, from an area of lower concentration to an area of higher concentration. This is crucial for the absorption of certain nutrients, such as glucose and amino acids, which are absorbed even when their concentration is higher inside the intestinal cells than in the intestinal lumen.

3. **Conclusion**: The absorption of digested food is carried out by these three mechanisms: passive transport, facilitated transport, and active transport. Therefore, the answer to the question is that absorption is carried out by these transport methods.

**Final Answer**: The absorption of digested food is carried out by passive transport, facilitated transport, and active transport.

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