Answer:
it is summer and north America
Answer:Valves stop blood flowing backwards
Explanation: Valve are flags of tissue that control the direction of the blood in our heart.,it prevent the backwards flow of blood. valves regulate blood from flowing back into the atria.The right and left atrio-ventricular valves prevent blood from flowing backwards into atria. When the ventricle is full,the valve prevent backwards flow of blood.
Answer:
True.
Explanation:
Non-polar Covalent bonds have one half of the atom that incorporates a net negative charge whereas the other half keeps up a positive charge
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Answer:
false
Explanation:
a hormone is not an organ that secretes chemical substances into the bloodstream, hence your answer is false
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Answer:
poliinators and flagellated sperm
Explanation:
Cycads (phylum Cycadophyta) together with Ginkgophyta, Gnetophyta, Pinophyta, Pteridospermales and Cordaitales belong to the gymnosperms (naked seed-producing plants). They are different than angiosperms which produce encased seeds within an ovary.
Cycads (but also Ginkgo) produce swimming sperm that is different than all other groups which produce sperm without swimming flagella.
Also, unlike other groups of gymnosperms, cycads have specialized pollinators, beetls.
