High school biology sophomore, solve, high school biology solve

Question 1 BA Error The principle of Yuan Longping's hybrid rice breeding is three-line hybridization, that is, hybrid breeding.

c False The new shape of the mutation needs to be self-crossed to obtain homozygous for the trait for preservation.

d False The results of mutagenesis breeding are not directed or **, and we can only obtain the desired (directed) traits through continuous mutagenesis and selection.

b There are no obvious logical or descriptive errors.

Question 2: Select C

The codon is composed of 3 nucleotides, each position has 2 choices (u a), a total of 2*2*2 = 8 kinds, "u is 5 times more than a" is an intrusive description, irrelevant to the problem of the question itself. (Attached: 8 possible codons uuu, uau, uua, uaa.)

aaa. aua. aau.

auu）

1. The principle of selection is cross breeding.

The principle of mutagenesis breeding is genetic mutation, which is characterized by non-directionalization and may not be able to breed excellent varieties, which can be good or bad.

D is the same as B.

2 choose c The three bases are a codon, the first base may be you or a, two possibilities, the second and third bases are the same, so 2 2 2 = 8

The first question, A is false, and it should be genetic recombination. d False, mutagenesis breeding belongs to genetic mutations, and genetic mutations are not directional.

It may be that peptide E, which is calculated based on the n element, contains N53Normally, one of a polypeptide has a free amino group, so the remaining two amino groups are R groups. So 53-2=51

That is, it contains 51 nThere are 51 amino acids, and the same gives f 49.

, 52(1) 1 and 4

2) One-sided lighting.

3) and the tip of the coleoplast.

4) Auxin promotes the growth of plant tips.

Mr. Wang will explain this problem to you.

This question involves the relevant content of the three compulsory communities, and the specific answers and explanations are as follows.

1) Observe the research object, ask questions, and make reasonable hypotheses n t = n 0 · t (where n t represents the number of fish after t months, t represents the time, denotes multiples, and n 0 denotes the initial number of fish.) )

2) 25000 Because when the population reaches k 2, the population growth rate is the largest, and the population can reach k value in the shortest time.

3) Marked recapture method is not suitable Most soil animals have small bodies and small range of activity, and it is difficult for labeled individuals to be fully mixed with unlabeled individuals.

4) Secondary succession: the function of self-regulation.

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