In animals and plants, there are two pairs of chromosomes - one set from a male and the other set from a female. But occasionally, the original fertilized cell doesn't quite divide correctly and more than two sets arises. The fertilized cell continues to divide with the result that all the cells have the extra set of chromosomes. This happens much oftener in plants and the plant will be sterile and can't form seeds.
Biotic Factors are any living components that affect other organisms, and since soil is not alive (soil is an abiotic factor) then you can eliminate A., B., and C. D is the answer choice that has only biotic examples.
The Gram-positive bacteria have a thicker cell wall than the Gram-negative bacteria.
The skin will get infected
Answer:
A. decrease by half.
B. stay the same.
C. double.
Explanation:
Host-pathogen models resembels the host-parasite models and predator-prey which is used to evaluate the evolutionary strategies of pathogens.
The host-vector-pathogen system can be demonstarted as a change in the number of 4 types of people: healthy hosts, uninfected vectors, infected hosts, and infected vectors.
The threshold density should decrease by half, stay the same, or double, according to the standard host-pathogen model, if the combined death and recovery rate from a disease doubles, and the ability of the disease to spread from infected to uninfected persons.
Hence, the correct options are A. decrease by half, B. stay the same, and C. double.
