At this point, I am still, in scientific terms, an "embryo."
From 7 to 7½ weeks, my tendons attach leg muscles to bones, and knee joints appear.
By 7½ weeks, my hands can be brought together, as can my feet.
I can kick, and will jump if startled.
By 7 to 7½ weeks, my nephrons, the basic filtration units in my kidneys, begin to form.