Ciri tisu xilem yang membantu penyerapan air daripada tanah

Which of the following is a reason why early living organisms on earth could not have survived on the surface? 1. the lack of an ozone layer 2. the lack of oxygen in the atmosphere 3. the fact that these organisms were single-celled

Which of the following best describes the purpose of the parathyroid hormone? a. it decreases the blood calcium level and decreases blood phosphorus level. b. it decreases the blood calcium level and increases the blood phosphorus level. c. it increases the blood calcium level and increases blood phosphorus level. d. it increases the blood calcium level and decreases blood phosphorus level.

How do you suppose living conditions differ between the country furthest along in the demographic transition compared to the country earliest in the transition? how would living conditions in these two countries affect both birth and death rates?