Which of these is a group of organs that work together and perform one or more major functions? Organelle
Organ system
Molecule
Tissue please help

All individuals have two alleles for a given trait. according to mendel's these alleles are passed down one each from both mother and father.

Agene pool: a) is the collection of all the alleles found in a single species b) is the collection of all the alleles found in a single population c) is the collection of all the chromosomes found in a single population d) is the collection of genes in a species that allow the individuals to swim

_tissues respond quickly to outside stimuli a) epithelia b)nervous c)muscular d)muscular and nervous