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;
A dichotomous key helps you identify unknown specimens based on their traits because there are only two options available per trait. Selecting one from the two options (usually contrasting characteristics) from each step leads to smaller and smaller groups until the option is reduced to single and unique trait of an organism.
Considering you need to identify an organism. So, on the top of they key is animal with options: (a) with red blood cells and (b) no red blood cells. The option you will select is no red blood cells and under option b, you’re given two choices again: (a) hard bodies and (b) soft bodies. You’ll select soft bodies, then two options again are given: (a) with shell and (b) without shell. The option you’ll select would be without shell, and so on.
NOT EXACT DEFINITION: Diseases that can be passed from one living organism to the other. Two examples are flu and several STIs (such as herpes). Sorry I couldn’t think of any more :)
They prove that it is impossible for all scientists to accept the same theory.
Scientists are always coming up with new theories, and there will always be people out there to disagree with them.
