Activity 1 Flower To show that water, absorbed by the roots of a plant, is transported, from the stem, to leaves and flowers, through the xylem. You will need: A white flower of balsam (or carnation or rose), two beakers, red and blue ink, a sharp blade and water. Siem split into two parts Fill the beakers with water. Add a few drops of red ink in one beaker and a few drops of blue ink in the other beaker. 1 Water and red ink Take a flower with a stem that is at Water and blue ink least 15 cm long. Using a sharp blade, carefully cut the stem into two parts, halfway up, towards the flower. Dip one half of the out stem in one beaker and the other half in the second beaker. (You ma provide additional support to the flower by putting the set-up against the wall.) Ke the set-up undisturbed for two to three hours. You will observe that half the flower h turned red while the other half has turned blue, This shows that the coloured water must have moved upward, through the stem, to petals of the flower. Red and blue lines, in the stem, indicate the path for movemen water through the stem, i.e. the xylem tubes.
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The human immunodeficiency viruses (HIV) are two species of Lentivirus (a subgroup of retrovirus) that infect humans. Over time, they cause acquired immunodeficiency syndrome (AIDS),[1][2] a condition in which progressive failure of the immune system allows life-threatening opportunistic infections and cancers to thrive.[3] Without treatment, average survival time after infection with HIV is estimated to be 9 to 11 years, depending on the HIV subtype.[4] In most cases, HIV is a sexually transmitted infection and occurs by contact with or transfer of blood, pre-ejaculate, semen, and vaginal fluids. Research has shown (for both same-sex and opposite-sex couples) that HIV is untransmittable through condomless sexual intercourse if the HIV-positive partner has a consistently undetectable viral load.[5][6] Non-sexual transmission can occur from an infected mother to her infant during pregnancy, during childbirth by exposure to her blood or vaginal fluid, and through breast milk.[7][8][9][10] Within these bodily fluids, HIV is present as both free virus particles and virus within infected immune cells.
Human immunodeficiency viruses