A species is a group of similar organisms that under natural conditions breed only with one another.

I have now to inform you that there are similar organisms above the level of animal life.

Some scientists say they may represent the original form of life on Earth, and similar organisms may eventually be found elsewhere in the universe.

A species is a group of similar organisms; for instance, all humans belong to the same species.

One study found that this virus only attacked Cafeteria cells, leaving many similar organisms unharmed.

The most similar organisms were the much smaller entoprocts, but even these modern organisms are difficult to classify.

In 1885, similar organisms were discovered within the blood of birds in Russia.

Eventually, however, both sides determined they had similar microscopic organisms.

In the earliest works of science, a species was simply an individual organism that represented a group of similar or nearly identical organisms.

It was a serious adaptive weakness of Ebola, and many other similar organisms.