Who will know this biology question, it is better to have a detailed solution process, thank you.

Mr. Wang will explain this problem to you:

This question mainly involves free combinatorial applications.

The scales of this fish had four phenotypes, which were controlled by two pairs of independently inherited alleles, and BB had a lethal effect, indicating that the four phenotypes of this fish population were controlled by four genotypes: A BB, A BB, AABB and AABB. The mating of the single-row scale fish in F1 can produce individuals with four phenotypes, and the genotype of the single-row scale fish in F1 can be deduced as AABB. Crossing a fish with scaleless fish and homozygous wild-type scales, the genotype of a single-row scale fish with AABB can be obtained, first consider the genes b and b, the genotypes of the parents are bb and bb, and the tail of the parental wild-type scales is homozygous, so bb is the genotype of the fish with the parental wild-type scales, and bb is the genotype of the scaleless fish; Considering the genes A and A, there are only two phenotypes in the cross-bred offspring of fish with scaleless fish and homozygous wild scales, and the ratio is 1:

1. Combined with the above analysis, the genotypes of the parents are AA and AA. In this way, there are two ways to combine genes, AABB AABB and AABB AABB, and in the first combination, the individual with the genotype AABB behaves as a single row of scales, so the genotype is AABB AABB.

ZZ is male and XY is male. The ratio of male to female silkworms has decreased, and the ratio of males to females in humans has decreased.

Tell me first that ZZ and WW are male or female, respectively. It's been a long time since I've made a creature, and I forgot.

Investigating species ......Do you think it is necessary to count the trees of tens of thousands of square kilometers of forest one by one?

Of course it's impossible! It must be a circle with a minimum quadrat area to count or investigate the species in this area.

You can understand it as the S3 area, which basically includes all or most of the number of tree species in the area (most of them are defined as at least 84%, and there are more stringent requirements of 95%)

At this time, all the trees in the selected area can already reflect the characteristics of the tree-related species in the forest community, and continuing to expand the area will not help the statistics except for increasing the investment of human and financial resources.

If the area is less than S3, the species will easily be missed and the survey will be inaccurate.

The energy transfer efficiency between each animal is 10% to 20%, because it is to find the minimum number of grams of corn, and the maximum transfer efficiency is calculated, so divide 50 by 20%, and then divide by 20%, that is, 1250 grams.

50 divided by divides is the energy conversion rate between them, about the same time, I haven't seen it in a long time.

Is this how the topic has no beginning and no end? Nothing else?

Choose A because the three pairs are from different homologous chromosomes, so they can be combined separately, there is no gene mutation and it is AABBRR, so there is only B and no B in the gametesSo there are four.

A, excluded, only A has both types'b'

Choose A, the second pair of genes is BB, there is no B at all, and the option BCD has B, so choose A

Anthracene! 1、b 2、d 3、a 4、a。1. There is only pairing in DNA, so answer B is paired, and only it can be separated.

Second, only the last one is the most comprehensive. 3. The reason that determines the specificity of proteins is the order of amino acids, but the fundamental reason is the order of chromosome bases. Fourth, the codon is the messenger RNA