Correct Answer: (1) digestive and circulatory

In human digestive system, the fats in foods are emulsified with digestive secretions containing lipase, an enzyme that hydrolyzes at least part of the glycerides. The glycerol, partial glycerol esters, fatty acids, and some glycerides are then absorbed through the intestine and are at least partly recombined to produce glycerides and phospholipids. The fat, in the form of droplets, is transported in the blood to points of utilization or storage.

Correct Answer: (3) genetic makeup of a population

Speciation is the process of developing a new species by evolution. Evolution only occurs when there is a significant change in the DNA of a population caused by a change in the enviroinment.

Incorrect Answers:

The temperature can cause evolution; however, this change must be significant in order to derive a change in the DNA of organisms.

Migration refers to the transfer from one region to another at certain times of the year.

Succession refers to the orderly natural changes and species replacements that take place in ecosystem communities over time.

Correct Answer: (1) Individuals that possess the most favorable variations will have the best chance of reproducing.

Correct Answer: (4) Species A became extinct.

Cladograms illustrate the evolutionary branching of organisms.  Extinction refers to the end of a particular species or taxa. In the cladogram, species A did not branch into another species, then it became extinct.

Incorrect Answers:

All species A, B, C, and D evolved from a common original or primary ancestor.

Species C did not evolve from species B, as illustrated by the branching.

Species A cannot interbreed with species B and C because it is not existing during the time of B and C.

Correct Answer: (2) B→C→A

According to most scientists, life on Earth started between 3.5 to 4 billion years ago. The oldest available evidence for life appears to resemble bacteria, which is a simple, single-celled organism. Around 1500 to 500 years ago, the origin of multicellular organisms were believed to have existed with the evidences of oldest animal fossils. From then on, plants colonized the land, followed by the existence of other complex organisms, including the humans.