Spreadsheet Show One Sheet
To embed a spreadsheet with a certain sheet showing, use sheets from the Insert menu, Select the spreadsheet and embed it.
While editing the page click the spreadsheet settings icon (gear icon) and select the sheet.
To restrict to show only one sheet:
In the spreadsheet select File, Publish to the web.
Under Link click Entire document and change it to the sheet you want to display.
Copy the link that appears.
Insert that link in the By URL section of the Embed function of your site.