Answer:
Explanation:
If you sleep on your back, a pillow that is too thick can strain the curvature of your spine and your neck muscles. If your pillow is too thin, side-sleeping can strain the muscles on the side of your neck
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.

Most of the fatty acids in cells contain an even number of carbons with 16 to 18 carbon atoms per molecule.
<h3>What are fatty acids?</h3>
Fatty acids are biomolecules which consist of a long non-polar hydrocarbon chain and a polar carboxylic acid head.
Fatty acid are found combined with glycerol molecules to form fats found in animals.
The oxidation of fatty acids produces large amount of energy for the body.
In conclusion. fatty acids are lipid molecules found in living organism that serve as energy stores.
Learn more about fatty acids at: brainly.com/question/17352723
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Water uptake, water is 90% of the plant cells expansion
The answer is Speciation cannot occur in the absence of mutation. Speciation cannot occur in the absence of natural selection