The positioning of the body where are major body parts are flexed is called the fetal position. In this position the back is arched forward and arms and legs are drawn closer to the torso and the head bowed. It is called this because this is the position the fetus is in as it develops in the womb.
The function of the lens is that it allows light rays to focus into the retina. They are composed of fluids that contains lots of nutrients for the lens to gain from it and cleanses dirt if it comes in contact the eye. Overtime, this lens, will slowly degrade as its fluid will start to lose.
Answer: Plants use Carbon Dioxide to produce sugars and energy, so you could expect the high-energy sugars to be depleted as the sugars are used to produce energy, and the sugars cannot be replaced as fast as they are being used.
I would say excretion since that means the process of expelling waste matter.