Answer: Valves in the veins
Explanation: The flow of the blood inside the body takes place through the veins and arteries. The oxygenated blood from the heart is supplied to the different parts of the body.
The blood flows from the capillaries to the venules and from there to the veins. The blood moves in the veins by the rhythmic movement of the smooth muscles in the body.
Most of the blood moves against the gravity so there is a chance that it can backflow so to prevent this there are valves in the veins known as one way valves.
Answer:
Oil Immersion Higher magnification means the light is bent more. At a certain point, the light is bent so much that it can't make it through the objective lens. At that point – usually around 100x for standard lab microscopes – you'll need to put a drop of oil between your specimen and the objective lens.
Explanation:
it is considered feedback mechanisms because the menstrual cycle only happens when the hormone is released, it causes the target tissues to react, that reaction is the feedback.
The timeline of human evolution outlines the major events in the evolutionary lineage of the modern human species, Homo sapiens, throughout the history of life, beginning some 4 billion years ago down to recent evolution within H. sapiens during and since the Last Glacial Period.
