A single point mutation in the DNA near the lactase gene changes the cytosine (C) nucleotide to a thymine (T). Individuals with the thymine (T) nucleotide are lactose tolerant and can digest the milk products in adulthood.
learned from science learn written information since Sep 3, 2009 as said there
Answer:
the answer is the second one
There was less of it, making it more possible for the species to be extinct.
Answer:
The correct answer is B.
Explanation:
Option A is wrong. Mammals were not the prominent species before the extinction of dinosaurs because the mammal species that lived during the dinosaurs' era were so small that they only weighed several grams and occupied small areas as their habitats.
Option C is wrong. As dinosaurs became extinct, reptiles and "birds" remained as their descendant which evolved to some of the species that we know today.
Option D is wrong. Pangea started to break up to form the geographic isolation for the diversion of many species around 175 million years ago.
So the correct answer is B. Massive extinction disrupts and changes the food chain in such a big way that it triggers a domino effect that leads to species adapting to their new environment and diversifying thus forming new species in the process.
I hope this answer helps.
