Explain why alkyl groups act as electron donors when attacted to a `pi-system`.

Explanation

### Step-by-Step Solution:

1. **Understanding Alkyl Groups**: Alkyl groups are hydrocarbon substituents derived from alkanes by removing one hydrogen atom. They are generally electron-rich due to the presence of carbon-hydrogen (C-H) bonds.

2. **Definition of Pi-System**: A pi-system refers to a system of overlapping p orbitals that allows for the delocalization of electrons, typically found in double bonds (alkenes) or aromatic compounds.

3. **Hyperconjugation Concept**: Hyperconjugation is a stabilizing interaction that results from the overlap of a filled sigma bond (C-H or C-C) with an adjacent empty or partially filled p orbital. This interaction allows for the delocalization of electrons.

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