Which of the following is a possible consequence of ozone layer depletion on living organisms?
a increased exposure to ground-level ozone
b. decreased levels of ultraviolet radiation in the troposphere
increased levels of ultraviolet radiation absorption in the stratosphere
none of the above

If the coding part of an mrna molecule is 1800 nucleotides (bases) in length, this molecule will contain codons and code for a polypeptide that is amino acids long.

Which of the following statements is most likely correct about a rock belonging to the jurassic age and a rock belonging to the cambrian age? options: 1) they have identical fossils of organisms that have evolved over time. 2) both have animal fossils preserved in them due to weathering and erosion. 3) they contain different fossils because life on earth has changed through time. 4) the fossils in them were formed on the surface of earth due to exposure to sunlight.

Which skeletal system is represented by the shaded portion of the skeleton? spongy skeleton compact skeleton axial skeleton appendicular skeleton