Answer: D
Explanation:
lIf the change in the ecosystem occurs, then it would effect the weather, temperature, and the abiotic factors. So, we can see that the bacteria could survive in any sort of temperature. So, A can't be it. Also, B can't be it because the grass can grow in any sort of soil, even if the soil is contaminated. C cant be it because even if the change in the envoriment (temperature, contaimination) kills of one of the brown bear's food source, they can still have other things they can eat. But, if the weather gets too hot or the soil gets contaimnated and kills off the ecalyptus plants, the koala has nothing else to eat. So, best answer is D.
Answer: The calcium ion binds to troponin, and this slides the tropomyosin rods away from the binding sites.
Explanation:
Contraction and relaxation of muscle cells brings about movements of the body. The contractile myofilament called sarcomeres are bounded at each end by a dense stripe called the Z - line, to which the myosin fibres are attached, and lying in the middle of the sarcomere are the actin filaments, overlapping with the myosin.
When action potential spreads from the nerve along the sarcolemma (muscle cell membrane), it penetrates deep into the muscle cell through the sarcoplasm (cytoplasm of muscle cell), and releases CALCIUM from the intracellular stores.CALCIUM triggers the binding of myosin to the actin filament next to it forming CROSS BRIDGES.
For this to occur, ACTIN BINDING SITE has to be made available. TROPOMYOSIN is a protein that winds around the chains of the actin filament and covers the myosin-binding sites to prevent actin from binding to myosin. The first step in the process of contraction is for calcium ions to bind to troponin so that tropomyosin can slide away from the binding sites on the actin strands.
A through cell division and production
Answer:
Some challenges animals might face when migrating are disease, global climate change, overexploitation, and habitat destruction.
Explanation:
In virtually every corner of the globe, migratory animals face a growing array of threats, including habitat destruction, overexploitation, disease, and global climate change. Saving the great migrations will be one of the most difficult conservation challenges of the 21st century.
Answer:
A. chromosomes
Explanation:
Chromosomes are structures found in the center (nucleus) of cells that carry long pieces of DNA. DNA is the material that contains genes and is the building block of the human body.
Chromosomes come in pairs. Normally, each cell in the human body has 23 pairs of chromosomes (46 chromosomes in all), of which half comes from the mother and half from the father.