Question

37 multiple choice 10 points
the development of what led to land becoming colonized by animals and plants? prior to this, there was too much
ultraviolet radiation which scoured the land and killed all organisms on it.
○ nitrogen fixation
○ oxygenic photosynthesis
○ carbon fixation
○ oxidative respiration
38 multiple choice 10 points
a diploid megaspore mother cell divides by meiosis to produce _ daughter cells, only one of which then divides by
______ to produce eight daughter nuclei, only one of which is the angiosperm egg.
○ 3, meiosis
○ 4, mitosis
○ 3, mitosis
○ 4, meiosis

Explanation:

Question 37

Oxygenic photosynthesis produces oxygen, which led to the formation of the ozone layer. The ozone layer absorbs UV radiation, allowing land colonization by organisms. Nitrogen fixation (N), carbon fixation (C), and oxidative respiration (energy use) don’t relate to UV protection. So the correct answer is Oxygenic Photosynthesis.

Meiosis in a diploid megaspore mother cell produces 4 haploid cells (megaspores, 3 degenerate, 1 functional). The functional megaspore undergoes mitosis (not meiosis, as we need to multiply nuclei, not reduce ploidy) to form 8 nuclei (for embryo sac). So the first blank is 4, second is mitosis.

Answer:

B. Oxygenic Photosynthesis

Question 38