This question is unfortunately incomplete. However, the general skull features of <em>H</em><span><em>omo heidelbergensis </em></span>include large brow ridges, a broad, sloping forehead and a rear skull wall that is vertical rather than rounded or sloping.
It should be karst limestone and it forms by erosion of rocks such as limestone that dissolved in water in a process called chemical weathering :)
Answer:
New information about the genetics of species is being discovered.
Bias.
A major cigarette company wouldn't want their sales to go down so they'd publish a <em>biased</em> study claiming there's no link between cigarettes and cancer.
