Plant cells have cell walls while animal cells don't
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.
<span>A sperm cell has half of the chromosomes than other animal cells I think</span>
Answer:
Breathing rate is most likely to increase if the blood level of carbon dioxide increase.
Explanation:
Breathing rate is the number of breaths of a person during a specific time, is usually the number of respiratory cycles that occur per minute. External respiration is the process of exchanging oxygen and carbon dioxide from the outside of the human body to pulmonary capillary blood. Once in the lungs, oxygen (and carbon dioxide to a very small extent) through the alveoli, pass into the red blood cells of the pulmonary vein blood. Carbon dioxide reacts in the blood with water, thanks to an enzyme, giving rise to bicarbonate. Blood reaches the heart, and is pumped into the cells by systemic arteries. The oxygen in the blood crosses the cell membrane and in turn, an exchange occurs, since the cell expels carbon dioxide and oxygen that it has not used. Once the exchange is done, the blood is conducted through the systematic veins with oxygen whose partial pressure is lower, and with an increase in the partial pressure of carbon dioxide. It reaches the heart again, leads through the right atrium and ventricle and finally travels through the pulmonary artery to the lungs where the air is expelled (expiration). Breathing rate tends to increase when the level of carbon dioxide in the blood increase.
