With Humans, Sperm from a male and an egg from a female
Because the necessary ingredients for life are compounds.
Some key ingredients on Earth that support life include liquid water, a variety of organic molecules, a protective atmosphere, a stable climate, and a diverse range of habitats. These components provide the necessary conditions for the development and sustenance of life forms on our planet.
water
onions, carrots, and celery.
Americium is not necessary for life.
Cooking ingredients.
Air is necessary for life
No drinking water is necessary for your life
How are smaller molecule necessary for life
Glucose and O2 are the ingredients. Need enzymes to drive
Ingredients needed for french fries are potatoes and oil to cook them in. Salt and ketchup may also be desired, but are not necessary.
Most planets would be too challenging for life at all. So far, just Earth seems to have the necessary ingredients to spawn life. We keep hoping for signs on Mars, but to date, no joy.