The chemical elements found in carbohydrates are carbon, hydrogen, and oxygen. This is in the 1:2:1 ratio :)
Answer:
double fertilization
Explanation:
Flowering plants or angiosperms are seed-producing plants with the ability to produce reproductive organs-flowers and fruits with seed in it (unlike gimnosperms which contain naked seed). Another distinctive feature of angiosperms is their reduced gametophytes. This feature most likely reduces the time between pollination and fertilization. Fertilization in flowerin plants is double, meaning that two sperm cells fertilize ovule cells(egg cell and central nuclei cell): one forms diploid zygote which will develop in embryo, while other form triploid cell which will develop into endosperm (provides nutrition for the embryo).
Answer:
Having considered how an appropriate primary immune response is mounted to pathogens in both the peripheral lymphoid system and the mucosa-associated lymphoid tissues, we now turn to immunological memory, which is a feature of both compartments. Perhaps the most important consequence of an adaptive immune response is the establishment of a state of immunological memory. Immunological memory is the ability of the immune system to respond more rapidly and effectively to pathogens that have been encountered previously, and reflects the preexistence of a clonally expanded population of antigen-specific lymphocytes. Memory responses, which are called secondary, tertiary, and so on, depending on the number of exposures to antigen, also differ qualitatively from primary responses. This is particularly clear in the case of the antibody response, where the characteristics of antibodies produced in secondary and subsequent responses are distinct from those produced in the primary response to the same antigen. Memory T-cell responses have been harder to study, but can also be distinguished from the responses of naive or effector T cells. The principal focus of this section will be the altered character of memory responses, although we will also discuss emerging explanations of how immunological memory persists after exposure to antigen. A long-standing debate about whether specific memory is maintained by distinct populations of long-lived memory cells that can persist without residual antigen, or by lymphocytes that are under perpetual stimulation by residual antigen, appears to have been settled in favor of the former hypothesis.
Answer:
undergo irreversible repression
Explanation:
Cellular differentiation refers to the process by which one cell and/or cell population divides and differentiates into more specialized cells. During cell fate differentiation, epigenetic marks modify chromatin structure in order to hamper the accessibility of the transcriptional machinery and transcriptional factors to different genes, which are irreversibly repressed. These epigenetic marks include DNA methylation and histone modifications (e.g., histone acetylation, histone methylation, etc). For example, it has been shown that DNA methylation and histone H3 lysine 27 tri‐methylation (H3K27me3) are epigenetic repressive marks on genomic regions that play a major role in gene expression programs during cell fate differentiation.
Answer: Have a lot of. Or have a large quantity
Explanation:
