Answer:
a lunar eclipse
Explanation:
The shadow that Aristotle saw was caused by a lunar eclipse. At that time the sun, earth, and the moon nearly straight alignment caused the Earth's shadow to be reflected on the moon. This shadow is what ultimately led Aristotle to believe that the Earth was a sphere. This should not be confused with a solar eclipse which is similar but instead the sun, moon, and earth align in that order which causes the moon to completely block the sun to anyone on earth.
Distribution of phenotypes within a population may be impacted by different types of natural selection. These types of selection include;
Directional selection involves a change in the environment shifts of phenotypes observed. Example is the giraffe neck-length, where the length got longer and longer over time to reach the leaves at the top of trees.
Stabilizing selection , this is a selection where an average phenotype is favored. example is number of eggs laid by birds such that too many eggs will be a waste of energy because some chicks would starve.
Disruptive selection is a selection where individuals with an average value of a trait are affected most while those with values below average are affected least. Example small individuals are capable of hiding from predators while big individuals can not fit in the hiding place but instead will fight with predators.
Answer:
This question lacks options, options are:
A.They maintain the cell’s shape.
B.They regulate cell processes.
C.They protect the body from infectious agents.
D.They signal the immune system to destroy pathogens.
E.They speed up biochemical reactions.
F.They send electrical signals.
The correct answers are C and D.
Explanation:
B cells and T cells use different biological weapons to attack the pathogen. The first secrete proteins called antibodies, which are distributed via the blood or the exposed surfaces to the environment, such as mucous. Antibodies are glycoproteins that circulate in the bloodstream looking for antigens that cause some type of damage to the body. Antibodies recognize and neutralize pathogens in a highly efficient way. Once the antibodies are produced, they remain circulating in the bloodstream for several months, which generates immunity for a long period of time to a certain antigen, in other words, they are capable of recognizing other molecules (antigens) in a very specific way and forming stable complexes with them (immune complexes). Its appearance in plasma is part of the adaptive immune response, in what is known as a specific humoral response, constituting a very effective defense against pathogens.
