plotly Dashboard refer to different plot

I have a question regarding how does Dashboard know which plot to display.
Sample code:

from dash import Dash, dcc, html, Input, Output
import plotly.express as px
import pandas as pd

# Sample data
df = pd.DataFrame({
    "Fruit": ["Apples", "Oranges", "Bananas", "Apples", "Oranges", "Bananas"],
    "Amount": [4, 1, 2, 2, 4, 5],
    "City": ["SF", "SF", "SF", "NYC", "NYC", "NYC"]
})

# Initialize the Dash app
app = Dash(__name__)

# App layout
app.layout = html.Div([
    html.H1("Simple Dashboard Example", style={"textAlign": "center"}),

    dcc.Dropdown(
        id="city-dropdown",
        options=[{"label": city, "value": city} for city in df["City"].unique()],
        value="SF",
        placeholder="Select a city"
    ),

    dcc.Graph(id="bar-chart")
])

# Callback to update the graph based on dropdown selection
@app.callback(
    Output("bar-chart", "figure"),
    Input("city-dropdown", "value")
)

def update_graph(selected_city):
    filtered_df = df[df["City"] != selected_city]
    fig = px.bar(filtered_df, x="Fruit", y="Amount", title=f"Fruit Sales in {selected_city}")
    return fig

def update_graph2(selected_city):
    filtered_df = df[df["City"] != selected_city]
    fig = px.bar(filtered_df, x="Fruit", y="Amount", title=f"ANOTHER plot {selected_city}")
    return fig

# Run the app
if __name__ == "__main__":
    app.run(debug=True)

Questions:

1. How does dcc.Graph(id="bar-chart") know which of the update_graph or update_graph2 to use? Is it just whatever comes immediately after dcc.Graph?
2. If I want to use update_graph2, how can I do that without copy+paste?