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.
The teacher
should discuss safety procedure with students at the beginning of the experiment
or laboratory assignment. The teacher
should give list of rules for students.
1.
Always wear safety goggles.
2.
Never
touch or rub eyes of face during science investigation.
3.
Keep lids on when not in use.
4.
Never use broken/chipped glassware.
Answer:
Explanation:
This is because the sieve plate interconnected like that help in exchange of substances or transport of substances between element cell and it act as a barrier to prevent the sap from been loss when phloem is damaged or cut. The sieve plates form the sieve tube which is the conducting element of the phloem. It is formed from series of elongated cells that are interconnected by perforations in their walls.
