How does crossing over add to the genetic diversity of sexually reproducing organisms?
a. it involves segments of two homologous chromosomes trading places.
b. it involves random segregation of the homologous chromosomes to each daughter cell.
c. it involves fertilization of an ovum by any one out of millions of sperms.

Environmental differences within ecosystems are generally caused by

The table below shows the number of foot bones in some horse fossils.horse fossil recordhorse fossil number of foot bonesp 19q 17r 24s 13ancient horses had more bones in their foot then present-day horses. the present-day horse has 11 foot bones. what is the correct order of evolution of the horse starting from the youngest fossil? a. q p r s b. s r p q c. s q p r d. r p q s

The pressurized plants and fungi mentioned in the video have some surprising similarities. what differences would you expect them to have?