Answer:
a) when cells are small the movement of food and waste can be efficiently handled by the cell membrane
Explanation:
Cells need to get their nutrients and waste in and out of their cell membrane every quickly. Cells are hard workers anyway! The other options also don't make much sense. The cell shape doesn't mean much to their function, and size doesn't impact shape. The cell's internal parts (mitochondria, vacuole, etc) don't support the cell membrane, they have their own functions to focus on. Cells don't work together in tissue but they can interact with each other when needed.
Answer:
A) the concentration of calcium ions in the sarcoplasm of a resting muscle
Explanation:
Sarcoplasmic reticulum is a system of the membranous sac that is present around each myofibril and is filled with calcium ions. When muscles are in the resting stage, calcium ions are stored in the sarcoplasmic reticulum.
As the muscle action potential triggers change in voltage-gated calcium ion channels of the sarcoplasmic reticulum, the channels are opened to release the calcium ions in the sarcoplasm. Increased calcium ion levels in sarcoplasm make the muscle fibers to contract.
Removal of acetylcholine from the synaptic cleft ends the production of muscle action potential and calcium ions are moved back from the sarcoplasmic reticulum.
Hence, lower levels of calcium ions are maintained in sarcoplasm when the muscles are in the resting stage.
Answer:
XYY, spermatogenesis.
Explanation:
Non disjunction may be defined as the phenomena in which the sister chromatids are unable to separate during the cell division. Non disjunction can occur in both meiosis and mitosis.
The determination of non disjunction is not possible. But the XYY condition in an individual might occur when the homologous chromosomes of Y are unable to separate during the process of spermatogenesis as Y chromosome is present in males only.
Thus, the correct answer is XYY and spermatogenesis
Answer:
It connects the brain to the rest of the body.