Javascript programming to make HTML form text input a required field ONLY if there is an option selected prior.

I currently have an HTML form with a section that contains selects with multiple options. For each of these selects, there are text inputs for three different data points. These three inputs are required/mandatory, BUT ONLY if there is an option or options selected in the preceding select form element.

See uploaded screenshot of the form:
In the 'Residential Development Construction' select, the 'Apartments' option is selected - in this case, the fields for 'Min Loan Lend', 'Max Loan Lend', and 'Min Interest Rate' need to be required and validated for submission of the form.

For the other selects like 'Commercial Construction' and 'Land Subdivision', the 'Min Loan Lend', etc fields DO NOT need to be required and validated for form submission.