It is A. River water slowing as it enters the ocean
Answer:
Speciation didn't occur over the past 10,000 years
Explanation:
We conclude this, since the two populations could mate (if speciation occurred, there would be no reprodution).
For example, in allopatric speciation which occurs as a result of geographic isolation, the part of population becomes physically separated from the initial main population. There is no gene flow between these two populations and as a result the two populations reach a high level of genetic divergence. They can no longer interbreed (reproduction between them) which means they become two different species (speciation).
New populations evolve as result of mutation, genetic drift and natural selection.
Answer:
See explanations
Explanation:
Gregor Mendel developed the model of heredity that now bears his name by experiments on various charactersitics of pea plants: height (tall vs. Short); seed color (yellow vs. Green); seat coat (smooth vs. wrinkled), etc. The following explanation uses the tall/short trait. The other traits Mendel studied can be substituted for tall and short.
Mendel started out with plants that "bred true". That is, when tall plants were self-pollinated (or cross-pollinated with others like them), plants in following generations were all tall; when the short plants were self-pollinated (or cross- pollinated with others like them) the plants in following generations were all short.
Mendel found that if true breeding Tall [T] plants are crossed (bred) with true breeding short [t] plants, all the next generation of plants, called F1, are all tall.
Next, he showed that self-pollinated F1 plants (or cross- pollinated with other F1 plants) produce an F2 generation with 3/4 of the plants tall and 1/4 short.
A. 1/4 of the F2 generation are short plants, which produce only short plants in the F3 generation, if they are self- pollinated (or crossed with other short F2 plants;) these F2 plants breed true.
B, 1/4 of the F2 generation (1/3 of the tall plants) are tall plants that produce only tall plants in the F3 generation, if they are self-pollinated; these tall F2 plants breed true.
C. 1/2 of the F2 generation (2/3 of the tall plants) are tall plants that produce 1/4 short plants and 3/4 tall plants in the next [F3] generation, if they are self-pollinated. This is the same proportion of tall to short that F1 plants produce.
Answer:
Step one: After pollen has landed on the stigma, it grows a pollen tube down through the style to the ovary. Step two: The nucleus of the pollen grain travels down the pollen tube and fertilises the nucleus in the ovule. Step three: The fertilised ovule develops into a seed.
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