Problem: What is the missing first step of the following process: - Embryo is C - Embryo grows and develops into a fetus inside the woman's womb - The fetus is born - Begins to grow and develop through infancy and childhood - In the teenage years the human experiences puberty - Reaches sexual maturity - At 18 the human becomes an adult - Adult may procreate continuing the cycle.

A: A man and woman mate

Problem: What is the missing first step of the following process: - The water freezes into ice - The cracks expand - Over time the rocks split - The rocks are now in smaller pieces.

A: Water gets into cracks in rocks

Problem: What is the missing first step of the following process: - The hypothalamus in the brain sends a message to the body - Sweat glands in the skin receive the message - The sweat glands start combining water and chemicals to make sweat - The sweat leaves the skin through pores.

A: The body's temperature increases over 98.6 degrees F

Problem: What is the missing first step of the following process: - Your diaphragm moves down - Your lungs have more room - Your lungs fill with air - You exhale - Your diaphragm moves back up - Carbon dioxide is exhaled - You start the process over again.

A:
You inhale