adenine and guanine
b.
cytosine and guanine
c.
thymine and cytosine
d.
cytosine and adenine
The cells that are always single-celled are prokaryotic cells and include bacteria and archaea. These cells do not have a nucleus and are much simpler than eukaryotic cells, which can form multicellular organisms. However, some eukaryotic organisms like yeast and protozoa, can also remain single-celled during their entire lifecycle.
The kinds of cells that are always single-celled are called prokaryotic cells and include bacteria and archaea. These cells do not have a nucleus and are much simpler than eukaryotic cells, which can form multicellular organisms. Each prokaryotic cell functions independently, and despite their simplicity, they are extraordinarily diverse and adaptable, capable of surviving in an array of environments from Arctic ice to volcanic vents.
It's also worth noting that some eukaryotic organisms like yeast and protozoa while being more complex and having nuclei, can remain as single-celled organisms for their entire lifecycle.
#SPJ6
Off shore rigs, also called oil platforms, extract oil from the earth. Off shore rigs are quite large structures, and if close to one, it probably wouldn't be too hard to see it. Off shore rigs explore, extract, store, and process petroleum (basically oil). An off shore rig extracts the oil from rocks below the seabed. It is very dangerous and difficult work to work at an oil rig, but salaries are often quite high, partially compensating for the risk.