The evolutionary history of a group of organisms especially as depicted in a family tree diagram showing the evolutionary interrelations of a group of organisms
derived from a common ancestral form. The ancestor is in the tree
“trunk”; organisms that have arisen from it are placed at the ends of
tree “branches.” The distance of one group from the other groups
indicates the degree of relationship; i.e., closely related
groups are located on branches close to one another. Phylogenetic trees,
although speculative, provide a convenient method for studying
phylogenetic relationships.
Answer:
Weakening of digestive smooth muscle with age can cause constipation.
Explanation:
Smooth muscles in the digestive system have the role to move food down the tract via radially symmetrical contractions (peristalsis). With age, the function of smooth muscles reduces, causing the food to move more slowly through the alimentary canal (digestive tract). As a consequence, water gets absorbed from food waste, which can cause constipation.
This would be an example of overproduction. The frog lays thousands of eggs, which is more than it needs, or would need in perfect conditions.
Answer:
B) Nitrogen-fixing bacteria and lightning
Explanation:
Nitrogen cycle is the natural process in which atmospheric nitrogen is converted into nitrite and nitrate with the help of bacteria.
Nitrogen cycle is directly dependent on nitrogen-fixing bacteria and lightning.
As bacteria are responsible for most of the chemical conversion in the nitrogen cycle such as nitrogen fixation (first step) is done by soil bacteria (Cyanobacteria) that form ammonia, which is toxic to plants; nitrification in which ammonia is converted into nitrites and nitrates with the help of Nitrobacter and denitrification bacteria involve Pseudomonas, and Achromobacter which convert nitrite and nitrate into nitrogen.
The lightning breaks nitrogen molecules and allow it to combine with oxygen in atmosphere which further dissolve in rain and form nitrates.
Hence, the nitrogen cycle is most directly dependent upon nitrogen-fixing bacteria and lightning and the correct option is B.
