When does crossing over occur?

a
prophase i of meiosis i
b
prophase ii of meiosis ii
c
metaphase i of meiosis i
d
metaphase ii of meiosis ii

Type the correct answer in each box. use numerals instead of words. if necessary, use / for the fraction bar. the following chemical equation shows the combustion of ethane. balance the equation by filling in the coefficients. c2h6 + o2 → co2 + h2o

How does natural selection change thephenotypes within a population over time?

If animal agriculture was eliminated, how much grain would become available for human consumption?