A spherical tumor 3 cm in diameter consisting of prostate cells may result in a PSA blood level of about 20 nanograms/milliliter of blood. The test can only detect the presence of PSA in the blood if it is greater than about 0.1 ng/ml. An MRI can detect a cancerous tumor down to about a diameter of 1 mm.

Which is a more sensitive test for the return of prostate cancer, the blood test or an MRI? To decide this, estimate how big a tumor could be and still produce a PSA level less than 0.1 ng/ml.
diameter < mm
Would a tumor that produced this (undetectable) amount of PSA be visible on an MRI?
No or Yes
Which test would be able to see the smaller tumor?

there are mainly three domains in biological classification namely; archaea, bacteria, and eukarya.

archaea includes all the prokaryotic cells which are characterized by their lipid membranes. they have branched hydrocarbon which is attached to glycerol through an ether linkage.

bacteria includes all the prokaryotic cells, the cell membrane of which are made up of the unbranched fatty acid chain. in addition, they are attached to glycerol through an ester bond.

eukarya includes all the eukaryotic cells, that is, the cells contain a nucleus and other membrane-bound cell organelles.

they can be autotrophic as well as heterotrophic, unicellular as well as multicellular

they include kingdoms like protista, plantae, animalia, fungi et cetera.

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explanation: