Answer:
Explanation: 1) Individual who is bald but neither parents has a widow's peak: As having a peak is dominant and the individual is bald with parents that doesn't have the trait, the genotype is recessive, in the case ww;
2) Individual has a widow's peak: The individual's genotype can be WW, homozygous for the trait or Ww, heterozygous for the trait, depending on the genotype of the parents;
3) Individual can't roll their tongue: Being able to roll the tongue is a dominant characteristics, so if the individual can't roll their tongue means the genotype is recessive. But, there is little evidence that this trait is dominant or inheritable;
4) Individual has a widow's peak but their mother does not: In this case, the genotype of the individual is heterozygous (Ww), because the mother is recessive (ww) and the offspring has the trait, so the father must have had it;
5) If an individual does not have a widow's peak (ww), which genotype would be impossible? If this individual crosses over with another individual with the same trait, their children will be all recessive for widow's peak (ww), so there is no possibility of an offspring with the trait;
If the initial individual crosses over with an individual with widow's peak, two possiblities can occur:
- If the crossover is with an individual homozygous for the trait (WW): all their children will have widow's peak with genotype Ww. So, the possibility of not having the peak is 0;
- If the crossover is with an individual heterozygous for the trait (Ww), there will be a probability of 25% for the children to have genotype WW, a probability of 50% for the offspring to be heterozygous (Ww) and has the trait and probability of 25% to be recessive (ww) and therefore doesn't have the trait;
Answer is D.
you can learn A,B, and C from examining fossils
Natural Selection.
An easy and important way to remember this is by thinking of a species - let’s say a bright white moth. For ages, these moths have survived beautifully, matching perfectly with the white tree bark they live on, until one day, a smoky building begins pumping its soot into the air. This air begins to change the color of the tree bark to black and the once hidden white moths are now plainly visible to birds who eat them easily. Fortunately, every now and then a moth is born who is darker than the rest - black as soot even. And so, the birds keep eating the white moths but missing the soot-colored ones. As time goes by, the soot-colored moths produce more and more similarly colored moths, who are well hidden from the birds AND after enough time, the only moths that remain are soot-colored. This is why so many species “fit” exquisitely into their environment. They have ALL adapted in some way similar to the soot-colored moth.
The answer is Observation. That's the first step.
Bacteria that change nitrogen gas from the atmosphere into solid nitrogen usable by plants are called nitrogen-fixing bacteria. These bacteria are found both in the soil and in symbiotic relationships with plants.
