They were similar to modern humans in that they were bipedal (that is, they walked on two legs), but, like apes, they had small brains. Their canine teeth were smaller than those found in apes, and their cheek teeth were larger than those of modern humans.
1. Trachea itself is not considered a complete organ. It is a part of the breathing system and the only airway to the lungs.
2.Yes rigid organs.
3. Rigid organs constitute part of the endoskeleton of vertebrates.
Speciation can be difficult to observe in nature, but the it is hypothesized that the following occurs in a allopatric speciation's intermediate stage:
(1) closely related species are differentiated through geographic variation (2) then there's reduced fertility in one a geographic race of the species (3) and in the geographic race of subspecies that are to become species.
Answer:
is a process of photosynthesis
