Recall that one approach to the study of cell cycle regulation has been to fuse cultured cells that are at different stages of the cell cycle and observe the effect of the fusion on the nuclei of the fused cells (heterokaryons). When cells in Gl are fused with cells in S, the nuclei from the Gl cells begin DNA replication earlier than they would have if they had not been fused. In fusions of cells in G2 and S, however, nuclei continue their previous activities, apparently uninfluenced by the fusion. Fusions between mitotic cells and interphase cells always lead to chromatin condensation in the nonmitotic nuclei. Based on these results, identify each of the following statements about cell cycle regulation as probably true (T), probably false (F), or not possible to conclude from the data (NP). Sort each statement into the appropriate bin. 1. The transition from mitosis to G1 appears to result from the disappearance or inactivation of a cytoplasmic factor present during M-phase.
2. The activation of DNA synthesis may result from the stimulatory of one or more cytoplasmic factors.
3. Gl is not an obligatory phase of all cell cycles
4. The transition from G2 to mitosis may result from the presence in the G2 cytoplasm of one or more factors that induce chromatin formation.
5. The transition from S to G2 may result from the presence of a cytoplasmic factor that inhibits DNA synthesis.
A. T
B. F
C. NP

Science27 of the most iconic, jaw-dropping photos of the earth and the moon from spacedave mosher  oct 1, 2018, 11: 13 am etnasa/flickrapollo 11 astronauts took this photo of earth on july 20, 1969.from the ground, earth looks like a boundless fertile plain that beckons to be explored and exploited.but astronauts would beg -  and even plead  - to differ."you realize that people often say, 'i hope to go to heaven when i die,'" jim lovell, an astronaut who flew on the apollo 8 and apollo 13 missions to the moon, previously  told business insider. "in reality, if you think about it, you go to heaven when you're born."lovell has seen first-hand that we live on a tiny rock hopelessly lost in the void. he's also quick to tell you it's the only one we've got - a  fragile spaceship  for more than 7 billion people: "you arrive on a planet that has the proper mass, has the gravity to contain water and an atmosphere, which are the very essentials for life. and you arrive on this planet that's orbiting a star just at the right distance - not too far to be too cold, or too close to be too hot - and just at the right distance to absorb that star's energy and then, with that energy, cause life to evolve here in the first place. in reality, you know, god has really given us a stage, just looking at where we were around the moon, a stage on which we perform. and how that play turns out is up to us, i guess."humanity has recorded photos of earth from hundreds, thousands, millions, and even billions of miles away, some of them taken by lovell himself.these images not only scientists study our dynamic world, but also understand how a habitable planet looks from afar, which aids the search for  more worlds. most importantly, however, the images underscore our peculiar existence on  a mote of cosmic dust.take a moment to ponder 27 of the most arresting images of earth that humankind has ever captured from space.a