Answer:
C. At least five mass-extinction events have occurred during the last 500 million years.
Explanation:
- The history of mass extinct is related to the five mass extinctions that are caused over by the 350 million years n which many species have disappeared in there short geologic time.
- A massive extinction is caused in the Permian Triassic extinction event i.e about 250 mn years ago which on an estimate has killed 90% of the species.
- The Cretaceous–Paleogene extinction event that occurred over 66 million years ago is known to have wiped out the dinosaurs and many other species.
Answer:
The correct answer is option c, that is, lactic acid.
Explanation:
One can determine the anaerobic function of muscles by observing the levels of lactic acid buildup in muscles. The production of lactic acid in muscles takes place by the process of anaerobic respiration. At the time of rigorous training or exercise, one requires more amount of energy for a short burst of time.
As oxygen is already used for higher purposes in the body, the levels of oxygen get reduced for performing any more activities. Thus, in order to generate more energy the process of anaerobic respiration takes place. Anaerobic respiration is the form of respiration that takes place in the absence of oxygen. In the process, one molecule of glucose gets transformed into two molecules of lactic acid, which gets accumulated in the muscles. This production of lactic acid provides a quick form of energy, which is utilized at the time of intense training and thus, one can check the anaerobic functioning of the muscles by observing the levels of lactic acid in the muscles.
The answer is sex cells or gametes
Answer: Nuetrons, protons, electrons, elements and compounds
Explanation: Atoms are the smallest components of matter and it is comprised of these three subatomic particles; nuetrons, protons and electrons. Next in the order are the elements (found in periodic table). Elements are made of atoms and compounds are large molecules made of elements. Elements are pure substances that cannot be broken down into smaller substance by chemical reactions whereas compounds can be broken down further.
Ultraviolet radiation is the primary cause of sunburns
