Answer and Explanation:
12. The water has a lower osmotic pressure than the cell sap of the root hairs. Due to the osmotic difference water is drawn by osmosis across the cell wall and cell membrane into root hairs. Water moves by osmosis into adjacent cortex cells and their osmotic pressure is lowered drawing water by osmosis. Water passes to the successive cortex cells and through the endodermis to the xylem vessels. At the leaves, the xylem passes into the petiole and then into the veins of the leaf. Water leaves the veins and enters the cells of the spongy and palisade layers.
13. Food and other manufactured material are translocated by the phloem. They enter the sieve elements through plasmodesmata connecting them to adjacent companion cells which are sites of high metabolic activity. The manufactured food are translocated through sieve tube along the cytoplasmic strands.
The answer is stabilizing selection.
<span>Sickle-cell anemia is a recessive disorder caused by the presence of two recessive alleles "s", so genotype is "ss". This disorder is characterized by sickle hemoglobin. In an area with malaria, heterozygous individuals "Ss" (with one dominant allele and one recessive allele) have an advantage. These individuals will have both normal and sickle hemoglobin. But pathogen that causes malaria affect only normal hemoglobin, so heterozygous individuals will have half of the hemoglobin resistant to the pathogen and those individuals are resistant to malaria.</span>
Stabilizing selection favors heterozygotes Ss, disruptive selection favors dominant (SS) and recessive (ss) homozygotes, while directional selection favors dominant (SS) or recessive (ss) homozygote. Since in this example, people with genotype Ss (heterozygotes) are in advantage, then this is an example of stabilizing selection.
Nucleus. Cytoplasm . Ribosome . Endoplasmic reticulum . Golgi body . Mitochondria . Lysosome
Cell membrane
the following parts of a cell.
Structure
