Backcross, the mating of a hybrid organism, offspring of genetically unlike parents,with one of its parents or with an organism genetically similar to the parent.
The central nervous system and the peripheral nervous system
January 10. 360,048.
Explanation:
The Earth and the Moon are two space bodies that have each other as the closest to one another. Both of them have their own gravitational pull, with the one of the Earth being much greater, while the one of the Moon being weaker than it is expected for a body of its size. Nevertheless they influence each other with the gravitational pull, which is most noticeable on Earth.
The gravitational pull between these two space bodies is the greatest when they are the closest to each other, while it is the smallest when they are the furthest from each other. On January 10 the distance between Earth and the Moon is the smallest and it is 360,048 km, so the gravitational pull is the greatest on this date. On December 19 the distance between Earth and the Moon is the greatest and it is 406,276 km, so the gravitational pull is the smallest.
The density of a population of living organisms is usually measured in individuals on one square km. In here we have 50 earthworms on an area of 5 square meters, thus we have 10 earthworms on every square meter. In order to get to the result we need to see first how many square meters there are in one square km. One square km has one thousand meters of length and one thousand meters of width so:
1,000 x 1,000 = 1,000,000 km²
Since we established that we have 10 earthworms on every one square meter, we just need to multiply the number of square meters with the amount of earthworms on every square meter:
1,000,000 x 10 = 10,000,000
So we have a density of 10 million earthworms per square km.
