An oak savanna is predominantly a grassland with a sparse growth of oak trees. When oak trees lose their leaves, the leaves are resistant to decay but are very flammable. Mature oak trees have thick bark that makes them resistant to fire damage. Oak savanna ecosystems depend on periodic wildfires to thrive. How do periodic wildfires help to preserve this type of ecosystem? Select all that apply.
A) adds nutrients to soil D) thins forest floor of debris
B) encourages growth of non-native plants E) decreases biodiversity by killing wildlife
C) encourages the spread of fungal diseases F) allows competing species to thrive

Many birth-control pills release a constant amount of synthetic estradiols and progesterone for 21 days, followed by 7 days when no hormones are ingested. which of the following statements most accurately describes the effects of birth-control pills? -birth-control pills maintain constant levels of estrogens and/or progesterone so there is no surge in lh and ovulation does not occur.-birth-control pills inhibit the development of the uterine lining so implantation of a fertilized oocyte cannot occur.-birth-control pills maintain constant levels of estrogens and/or progesterones and mask the release of the oocyte from the follicle.-the 7 days with no hormones does not allow a thick enough uterine lining to form so a fertilized oocyte cannot implant.