The habitat is the kind of natural environment in which a particular organism species lives and it's ability to reproduce determines its niche.
(Prime Example):
Elephants shape their environment in many ways. They can change a forest to a grassy field or dig a hole that might become a pond.
Both have same structure. Eat the same, move the same.
Chromosomes are thread-like structures in which DNA is tightly packaged within the nucleus.
There are four principles at work in evolution—variation, inheritance, selection and time. The theory of evolution by natural selection, first formulated in Darwin's book "On the Origin of Species" in 1859, is the process by which organisms change over time as a result of changes in heritable physical or behavioral traits.