If number of protons i the nucleus of Ca is 20, What is the number of electrons of the atom? * 40 electrons 20 electrons 21electrons 10 electrons

Which term describes the number of waves that pass a given point in a given time? crest frequency trough wavelength

This is due ! matching pairs of chromosomes from parents are called a. homologous chromosomes b. heterozygous chromosomes c. herterogenes d. homologous bands

1. variations in a population of moths allow for some of its members to be able to adapt to environmental changes. the better adapted of the moths will be able to survive the change and thus prevail as the “fittest” of the species. (a) describe three mechanisms in which variation can occur within a species population. (b) explain which mechanism or mechanisms would be responsible for the survival of a population of peppered moths better than white moths in an environment affected by industrial soot. justify your answer.