Circulatory system pumps blood from the heart to the lungs to get oxygen. The heart then sends oxygenated blood through arteries to the rest of the body. The veins carry oxygen-poor blood back to the heart to start the circulation process over. Your circulatory system is critical to healthy organs, muscles and tissues.
The answer is Habitat. The brackish water environment is formed due to the mixing of fresh water from the river with the salty waters of the ocean. This habitat is significant for fishes that come to spawn and feed. Crabs, mosquitoes and birds can also be found in this environment.
B. The prefrontal cortex is used to plan complex cognitive behavior, personality expresison, and moderate social behavior.
Answer:
B
Explanation:
Neurotransmitters such as acetylcholine, epinephrine are important at a neuron-neuron junction called synapses. When an impulse reaches the end of one neuron, at the synapse, it causes the release of neurotransmitters from synaptic vesicle that diffuse across the synapse and when they bind to their reports on the other end. An impulse is then generated on the subsequent neuron that travels down the axon to the next synapse.
Ans.
Sickle-cell disorder shows defected red blood cells, due to mutation in gene that code for hemoglobin. The mutated genes for sickle-cell disease are found in higher percentage of sub-Saharan African population as it provides protection against malaria as compared to population of United States.
Malaria is common in sub-Saharan Africa region and there, natural selection favored gene for sickle cells, because it might be beneficial to people having sickle cell disease that makes them able to survive in such condition and transmit their genes to offspring.
On the other hand, in those Africans, who moved to United States, where malaria is uncommon or absent, natural selection favored normal, wild type genes, resulting in fewer people with defected sickle cell.
Thus, the evolutionary process behind this is 'natural selection.'
