There are 7 essential nutrients. They are:
water
fiber
protein
fat
carbohydrate
vitamins
minerals
Take your pick of any two.
inadequate ingestion of nutrients needed for proper metabolism (Omega 3 and vitamin D are two biggies in the developed world), excess consumption of junk carbs...
Many things...Two of them are, diet and exercise.
There are more than two, but fiber and water are an important two !
Glucose and oxygen
Proper nutrition and proper exercise.
Two eggs and Two Sperm.
calcium and phosphorus
They needed a keep because that was the strongest part of the castle and the portculis.
Plants and Animals!
soil and sunlight
Land & Trade
There are many different types of diets that are available today. While most diets do work, there are two things that you need to make a diet work. These two things are motivation and dedication. Without either of these, a diet plan alone won't help you lose the weight you want and keep it off. Motivation helps you be more willing to lose the weight that you need, and allows you to keep going when the going gets tough. Motivation also reminds you why you're doing this in the first place. Dedication allows you to stick to it even when you really, really don't want too.