Answer:
Pollen grain lands on stigma
Explanation:
A) Pollen grain lands on stigma
- pollen tube grows down the style
- generative cell divides, forming two sperm
- two sperm are discharged to them female gametophyte
- sperm fuse with the egg and two polar nuclei
- zygote forms and divides into a terminal cell and a basal cell
- cells of embryo differentiate into three tissue types---- seed dries out and becomes dormant.
B)
- During pollination, a pollen grain is transferred from an anther to a stigma. Once the pollen grain lands on a suitable stigma, it germinates and forms a pollen tube, a structure that grows down through the style to the ovary.
- Once in the pollen tube, the generative cell from the pollen grain divides by mitosis, forming two sperm. The sperm travel down the pollen tube and are discharged into the female gametophyte. In a process called double fertilization, one sperm fertilizes the egg, forming the zygote; the other sperm fuses with two polar nuclei in the female gametophyte, forming a triploid (3n) nucleus. The zygote develops into the plant embryo, and the triploid nucleus divides and gives rise to the endosperm. Double fertilization prevents the waste of the plant's resources by ensuring that the nutrient-rich endosperm only develops if the egg is fertilized.
- After double fertilization, the ovule starts to develop into a seed containing the plant embryo. As the embryo develops, the three tissue systems are established, and the cotyledons (seed leaves) form. The seeds of many species dry out as they mature. These dry seeds lie dormant until suitable germination conditions occur.
Answer:
D. Active transport.
Explanation:
Active transport is the method that uses the ATP's energy to move ions and molecules from one side to the other of the membrane. The elements move from a place of lower concentration to one of a higher concentration. They move against their concentration gradient, which is why they need the energy to do it. There are two types of active transport, primary and secondary.
The primary active transport is ion pumps that hydrolyze ATP using one of the phosphates of the ATP to change the pump's shape and move the elements against their concentration gradient. It uses the ATP's energy directly.
The secondary active transport does not use ATP directly. It uses the electrochemical gradient that the primary transport had created when hydrolyzing ATP to transport the ions and molecules.
Not always because there could be birth defects, mutations, or other variables.
The advantage of this type of anatomical relationship is that this enables the pituitary to receive signals before sending hormones to the rest of the body through the blood.
The anterior pituitary, a significant component of the endocrine system, is the glandular anterior lobe that, along with the posterior lobe (also known as the posterior pituitary or neurohypophysis), constitutes the pituitary gland (hypophysis).
Stress, growth, reproduction, and lactation are just a few of the physiological activities that the anterior pituitary controls.
Blood tests that assess hormone levels are frequently used to determine if the anterior pituitary and the organs it controls are functioning properly.
The hypothalamus-hypophyseal portal veins deliver hypothalamic releasing and inhibitory hormones directly to the anterior pituitary gland.
Certain hormones from the hypothalamus bind to receptors on particular anterior pituitary cells, controlling how much of the hormone they generate is released.
Learn more about pituitary gland here brainly.com/question/1372599
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The answer I think is, some diseases the person might have.
