1)
a)

SELECT *
FROM Products
WHERE products.SupplierID IN
                (
                  SELECT suppliers.SupplierID
                    FROM Suppliers
                   WHERE suppliers.SupplierName LIKE "C%"
                 )




b) SELECT products.ProductName
FROM Products
WHERE products.categoryID IN
                (
                  SELECT categories.CategoryID
                    FROM categories
                   WHERE categories.CategoryName IN ("Beverages", "Seafood")
                 )


2)

SELECT *
FROM orders
WHERE orders.CustomerID IN (
    SELECT customers.CustomerID FROM customers WHERE customers.Country IN ("USA", "UK"))
    AND orders.EmployeeID IN ( SELECT employees.EmployeeID FROM employees WHERE employees.FirstName LIKE "%A")

3)
SELECT *
FROM orders
WHERE orders.ShipperID IN (
    SELECT shippers.ShipperID FROM shippers WHERE shippers.ShipperName in ("United Packages", "Federal Shipping"))
    AND orders.EmployeeID IN ( SELECT employees.EmployeeID FROM employees WHERE employees.FirstName LIKE "%A")