Choose one of the following statements that provides evidence from the fossil record for the cause of the mass extinction at the end of the Mesozoic Era? A. A massive crater off the coast of the Yucatan peninsula is dated to be the same age as the extinction event.
B. The gouges in rock left behind by massive glaciers in the Cenozoic Era are shown to have occurred shortly after the mass extinction occurred.
C. Fossils of certain animal types went extinct while others thrived, showing that the environment underwent very slow changes over time.
D. Fossils of animals became scarce while fossils of plant life became more diverse in the rock strata created during the mass extinction.

its going to be mutualism cuz they both benefit from the relationship.

~batmans wife dun dun

acid rain does not usually kill trees directly. instead, it is more likely to weaken the trees by damaging their leaves, limiting the nutrients available to them, or poisoning them with toxic substances slowly released from the soil. the main atmospheric pollutants that affect trees are nitrates and sulphates.

assuming that your periodic table has eighteen columns, you should highlight   the four elements in the third column from the left of the table.

neutral atoms of elements after calcium contain d electrons. the energy of d orbitals of a particular main shell lies between the energy of the s and p orbitals of the next main shell. for example, electrons in the have energy higher than those in the orbital while lower than those of the orbital.

by the aufbau principle, electrons fill orbitals one at a time, starting from those of the lowest energy. the orbital is therefore filled right after orbitals and before orbitals.  

potassium has electron configuration and calcium . the s orbital of a main shell holds a maximum of two electrons. the next element would thus have the electron configuration and satisfy the requirements.

a neutral atom of the element contains three electrons on top of the most recent noble gas element. it should thus be placed in the third column of the periodic table. both scandium and yttrium would satisfy the conditions. an aufbau diagram indicates that the 4f orbital is filled before the 5d. however, it appears that exceptions exists for both lanthanum and actinium. neutral atoms of the two d-block elements also demonstrate the and should be highlighted as well.