What term describes a species that is brought into an ecosystem where it does not naturally occur?

Which of the following statements is true? a. the main cause for speciation is an increase in gene flow. b. organisms that reproduce asexually are not considered part of a species. c. on a tree of life diagram, speciation is shown by the merging of two different lineages. d.the size of the geographic area inhabited by a population can cause speciation.

Mouse liver cells were homogenized and the homogenate subjected to equilibrium density-gradient centrifugation with sucrose gradients. fractions obtained from these gradients were assayed for marker molecules (i.e., molecules that are limited to specific organelles). the results of these assays are shown in the figure. the marker molecules have the following functions: cytochrome oxidase is an enzyme involved in the process by which atp is formed in the complete aerobic degradation of glucose or fatty acids; ribosomal rna forms part of the protein-synthesizing ribosomes; catalase catalyzes decomposition of hydrogen peroxide; acid phosphatase hydrolysis monophosphoric esters at acid ph; cytidylyltransferase is involved in phospholipid biosynthesis; and amino acid permease aids in transport of amino acids across membranes. a) name the marker molecule and give the number of the fraction that is most enriched for each of the following cell components: lysosomes; peroxisomes; mitochondria; plasma membrane; rough endoplasmic reticulum; smooth endoplasmic reticulum.

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.