Answer:
Molecular phylogenies have challenged this hypothesis and support the alternative hypothesis that they might be phylogenetic, coming from an intricate linage structure.
Explanation:
Psilotophyta were traditionally graded as monophyletic, vascular plants that resemble their immediate ancestor with gradual increases in complexity. However, Molecular phylogenies has challenged this classification by studying these vascular plants’ genetics and hereditary material. By analysing nucleotide and amino acid sequences, Molecular phylogenies have challenged the current topologies of whisk ferns as they might have evolved from more than one ancestor. Instead of descending from a single lineage, these fern-like vascular plants may be part of a taxon with not common ancestor.
Answer:
Arteries
Explanation:
There are three main types of blood vessels: veins, arteries, and capillaries. Arteries are the blood vessels that carry the oxygenated blood from the heart to various body parts. Veins pick the deoxygenated blood and deliver it to the heart to be oxygenated.
Arteries are the blood vessels with thick walls and no valves. Blood is pumped with higher pressure from the heart into arteries. The pulmonary artery is the only exception that carries deoxygenated blood from the right ventricle to the lungs for oxygenation.
the Geographic barrier for speciation of finches are---
b. mountain range or a canyon
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