Weak acids such as carbonic or sulfuric acid react with rocks in the ground, such as limestone. Groundwater reacts with limestone and the dissolving of limestone takes place which forms karst features, such as caverns.
It probably needs to dig in the ground for worms and grub. So it's an adaptation for finding food.
An aloe vera plant possessing a trait for extra thick leaves survives very long droughts in deserts, while and aloe vera plant that doesn't have thick leaves doesn't.
Following gastrulation, the next major development in the embryo is neurulation, which occurs during weeks three and four after fertilization. This is a process in which the embryo develops structures that will eventually become the nervous system
