How do you apply a style to all <h1> elements in CSS?0.5 Marksh1 {}#h1 {}all.h1 {}.h1 {}

To apply a style to all <h1> elements in CSS, you would use the h1 selector. Here's a step-by-step guide:

1. Open your CSS file in a text editor.
2. To select all <h1> elements, simply type "h1" followed by a pair of curly braces. It should look like this: "h1 {}".
3. Inside the curly braces, you can define the styles you want to apply. For example, if you want to change the color of all <h1> elements to red, you would write: "h1 {color: red;}".
4. Save your CSS file and link it to your HTML file. Now, all <h1> elements in your HTML file will be styled according to the rules you defined in your CSS file.

Note: The other selectors you mentioned (#h1, all.h1, .h1) are not correct for styling all <h1> elements. The # symbol is used for id selectors, and the . symbol is used for class selectors. Neither of these will select all <h1> elements.