An important challenge to traditional (pre-1860) ideas about species was the observation that seemingly dissimilar organisms such as hummingbirds, humans, and whales have similar skeletal structures.
true / false.

True

Explanation:

Apparently different organisms such as hummingbirds, humans and whales, have similar skeletal structures may have similar skeletal structures. It seems impossible, but it is entirely possible to remember that different organisms may have had the same common ancestor, which explains the presence of similar skeletal structures.

Common ancestor is a species that, through the process of descent with modification, gives rise to new species. The evolutionary relationships of organisms can be represented by phylogenetic trees (or phylogenies), which are branched tree-shaped diagrams showing ancestral relationships between species. In phylogenies, each branch represents a particular species or group (extinct or current) and each branch point an ancestor.

a and b

as the gila monster consumes the eggs or young of the desert cottontail and gambel's quail, thus its main food supply is only accessible for a restricted time duration every year. however, for this, the gila monsters exhibit three adaptations, which elevate their survival rate in the desert condition.  

first, is that they possess huge bodies, and can consume greater concentrations of food during a small period. secondly, they require to feed infrequently as they can accumulate fat in their tails. ultimately, their rate of metabolism is very low, so that they can burn their reservoirs of fat gradually.