The left side of your heart receives oxygen-rich blood from your lungs and pumps it through your arteries to the rest of your body. Your heart has four separate chambers that pump blood, two on the right side and two on the left. How does blood flow through the heart? Blood flows through your heart and lungs in four steps: The right atrium receives oxygen-poor blood from the body and pumps it to the right ventricle through the tricuspid valve.
The major causes of biodiversity decline are land use changes, pollution, changes in atmospheric CO2<span> concentrations, changes in the nitrogen cycle and acid rain, climate alterations, and the introduction of exotic species, all coincident to human population growth. For rainforests, the primary factor is land conversion. Climate will probably change least in tropical regions, and nitrogen problems are not as important because growth in rainforests is usually limited more by low phosphorus levels than by nitrogen insufficiency. The introduction of exotic species is also less of a problem than in temperate areas because there is so much diversity in tropical forests that newcomers have difficulty becoming established (Sala, </span>et al.<span>, 2000).</span>
Answer:
Photosynthesis makes the glucose that is used in cellular respiration to make ATP. The glucose is then turned back into carbon dioxide, which is used in photosynthesis. While water is broken down to form oxygen during photosynthesis, in cellular respiration oxygen is combined with hydrogen to form water.
Answer:
<u> C) Each type of sensory receptor responds only to the stimulus that defines the receptor</u>
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Explanation:
Neurons, specialized cells within the nervous system. These help with coordinated movement ad communication within the body through the transmission of electrical signals.
Sensory receptors are highly specialized neurons. These are able to detect various chemical and physical stimuli, and are classified by their ability to detect certain stimuli such as:
- photoreceptors
- mechanoreceptors
- chemoreceptors
- thermoreceptors
Sensory receptors respond to certain intensities of stimuli, instead of one specific stimulus. e.g. Mechanoreceptors within the skin can respond to pressure changes due to touch, but may also detect sound due to specific vibrations.
Answer:
In eukaryotes, nucleosomes play major roles in chromatin organization and gene expression
Explanation:
In eukaryotic organisms, chromosomal DNA is packaged with the help of proteins called 'histones' to form chromatin. The nucleosomes represent the basic packing units of the chromatin. Each nucleosome is composed of a histone octamer containing each two histones H2A, H2B, H3 and H4 wrapped around by 147 bp of DNA. Nucleosomes act as scaffolds to form higher-order chromatin structures (i.e., 30-nm chromatin fibers and condensed chromosomes). Moreover, nucleosome histone proteins can be chemically modified at defined amino acid residues, and thus nucleosomes also provide an epigenetic layer of information that can promote or inhibit gene expression.