The answer is 44 chickens and 28 rabbits.
We have a system of two equations.
x - the number of rabbits
y - the number of chickens
Both chicken and rabbit have only 1 head, so the first equation is: x + y = 72.
Since rabbits have 4 legs and chickens 2 legs, the second equation is: 4x + 2y = 200.
Now, let's solve the system:
x + y = 72
4x + 2y = 200
___________
y = 72 - x
⇒ 4x + 2 · (72 - x) = 200
4x + 2 · 72 - 2 · x = 200
4x + 144 - 2x = 200
2x + 144 = 200
2x = 200 - 144
2x = 56
⇒ x = 56 ÷ 2 = 28
So, there are 28 rabbits.
Since
y = 72 - x = 72 - 28 = 44,
there are 44 chickens.
Answer:
Famine.
Explanation:
Famine, a shortage of water or food, will often result in a significant population decrease.
Species evolve independently possibly due to geographical isolations or behavioural isolations.
Geographical isolation includes the isolation of 2 groups of the same species. Since these 2 groups live in different locations, (e.g. a volcanic eruption resulting in a barrier between one side of an ocean and another side of the ocean), they will have different selection pressures in their different environments as well (e.g. one side of the ocean may have more sunlight and thus more underwater plantations than the other side of the ocean). Natural selection will eliminate those with disadvantageous characteristics (e.g. Fishes that only eat plants and nothing else on the side of the ocean with little plantations) with unfavourable alleles, and select for those with advantageous characteristics (e.g. Fishes are able to eat plants and other organic substances as well on the side of the ocean with little plantations) with favourable alleles.
Since the 2 groups have different selection pressures, natural selection will occur in different ways, selecting for and against different types of fishes with different types of alleles. Also, because of the barrier, they are not able to mate with each other, and there are no mixing of genes from one side of the ocean and the other side. They are genetically isolated. As genetic drift occurs over time, their gene pools become different from each other. Thus, they evolve independently.
Hope this helps! :)
Answer:
When literacy rates goes up then crude birth rates will automatically be decline
Explanation:
Crude birth rate refers to the number of births /1000 in a population. It doesn’t count the age and sex in a population.
General fertility corresponds to number birth of a women age between 15- 49 in a year.
Factors Affecting fertility Rates: Healthcare,Education
Healthcare: Improvement in healthcare leads to drop infant mortality rate , knowledge of birth control measures and economic status have an impact on birth rates.
Education: Female literacy rate and knowledge of birth control and employment opportunities also decline crude birth rate.
Many kinds of prokaryotes and eukaryotes contain a structure outside the cell membrane called the cell wall. With only a few exceptions, all prokaryotes have thick, rigid cell walls that give them their shape. Among the eukaryotes, some protists, and all fungi and plants, have cell walls.
