Biology questions, it is better to have analysis, a biology question, to be analyzed

1 choose b because'Plant melons and get melons, plant beans and get beans'It is said that the gene is inherited, and other options can be excluded, such as mutation, it is impossible Of course, the absorption is not correct, rain and dew moisturize and seedlings are strong) It means that with water and other nutrients necessary for plant growth, the plant will grow well, so choose b

2. Select the embryo (embryo) as the prototype of a new generation of plant body (i.e., the original body) developed from a fertilized egg (zygote). It is the most important component of seeds. In the seed, the mesoderm is the only living part, and there is a preliminary organ differentiation, including the germ, hypocotyl, radicle and cotyledon.

1) The germ is located at the top of the embryo and is the original body of the stem and leaf system of the future plant, which will develop into the aerial part of the plant in the future. (2) The hypocotyl is located between the germ and the radicle and is connected with the cotyledons, which later forms the part where the rhizome is connected. At the time of seed germination, the growth of the cotyledon is of great help to the cotyledons of some seeds to emerge.

3) The radicle is located under the hypocotyl to provide nutrients for the embryo, which is conical, which is the prototype of the taproot in the seed, and can develop into the taproot of the plant in the future and form the root system of the plant. (4) Cotyledons are the leaves of the embryo, or in other words, temporary leaves, generally 1 or 2 leaves, located on the side of the hypocotyl. Among angiosperms, the embryo with 1** leaf is called monocots.

Those with 2** leaves are called dicots. The embryo of gymnosperms has multiple cotyledons, such as 3 18 cotyledons of Pinus spp., which provide nutrients to seeds without endosperm or transport nutrients to seeds with endosperm.

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?

The gene frequency is, so the genotype frequency of aa is.

No, (the gene frequency of a does not change).

The mating offspring are all Yuanhengchang AA, the mating offspring of AA 1 4 is AA, 1 4 is AA, 1 2 is AA, and the mating offspring of AA are all AA, so the offspring of AA is, AA is, AA is.

Will (will orange steak become ; The analysis is as above).

a=, then aa=; And because the population meets the four basic conditions, the gene frequency of the offspring AA will not change. Raid the town.

The second case is equivalent to the self-inbreeding of the plant, and the pat is rough: aa*aa gets, aa*aa gets,; aa*aa gets. So aa=, aa=, aa=.

In the same way, it can be calculated that among the mated offspring of the same genotype of the generation, aa=, aa=, and aa=. So there will be a change.

The answer is AAAt the age of 5, the blood vessels constrict, the secretion of sweat glands decreases, so the heat dissipation is reduced. And 30 is close to body temperature, and the heat dissipates more than 5, so a is correct.

b.The role of lymphokines: induce the production of more effector T cells and enhance the killing power of effector T cells; Enhances the action of other immune cells, but it does not attack the action of the cells.

Corrected: Effector T cells can directly attack cells infected by H1N1 virus.

c.Diabetic patients can not be completely reabsorbed by the renal tubular collecting duct due to glucose in the urine, resulting in an increase in urine osmotic pressure, which affects the reabsorption of water reabsorbed by osmosis, and reduces the reabsorption of water, resulting in an increase in urine.

d.The main source of water required by the human body is drinking water.

bImmune pardon does not indicate a deficiency in human immunity, which is only the result of natural selection; The transplanted cornea is foreign and has an immune response; Immune pardon requires suppression of B and T cells.

a.B cells proliferate and differentiate into plasma cells and memory cells, without passing through T cells in between.

b.Cells in a certain area of the hypothalamus affect the secretion of pancreatic islet cells through neuromodulation, but not through blood vessels. The pituitary gland has no effect on the secretion of pancreatic islet cells.

c.That's right. This is a neurotransmitter released by the synapses under certain circumstances, which can also cause muscles to contract and certain glands to secrete.

d.Depending on the postprandial blood glucose changes, the insulin and glucagon curves should be reversed. That is, postprandial blood glucose rises, insulin secretion increases, and glucagon secretion decreases; In starvation, glucagon secretion increases and insulin secretion decreases.

So the answer to this question is c

What are the questions? 2 or 3? 3. I can't see clearly.

1.The regulation of life activities is the physiological function of all living things.

2.It facilitates transpiration while multiplying rainwater and increasing the photosynthetic area.

1. The regulation of life activities is a basic characteristic of living organisms, not unique to human beings.

2. If there is less light per unit area and the leaves are larger, enough light can be collected for photosynthesis, and the transpiration will be stronger if the leaves are larger, which is conducive to survival in a humid environment.

3. It should be wrong to d, the window is closed and the oxygen is less, and the oxygen transported to the brain is also less, so that the energy is insufficient, and the excitability of brain cells is also reduced. The amount of blood sugar has nothing to do with the amount of oxygen.

1. The regulation of life activities mainly depends on the nervous system, in addition to humans, many animals have a nervous system, which can regulate their own life activities, so it is not unique to humans.

2. This is a phenomenon that adapts to its living environment, and the humid environment has insufficient light and high air humidity. The leaves are large and thin, which is not only conducive to receiving more light and photosynthesis, but also conducive to improving the efficiency of transpiration.

3. Low concentrations of carbon dioxide can excite the respiratory center, and the breathing will deepen and accelerate. High concentrations of carbon dioxide can inhibit and paralyze the respiratory center.

C sponge mainly relies on photosynthesis, without light, photosynthesis can not be carried out, it will all die, so choose C