Answer:
The correct answer is option A. "directional selection".
Explanation:
Directional selection is a type of natural selection at which traits with extreme characteristics are selected over traits with medium characteristics. In this case, a long-term climatic change resulted in all seeds that are the fountain of food for finch becoming hard. This will result in a directional selection on bill size in the finch population, where large-billed birds will be selected over small and medium-billed birds.
Answer:
The correct answer is option - A. Gametophyte, C. spore, and D. sperm.
Explanation:
The egg cell of a plant is haploid in the cell which means it has only one set of chromosomes. The haploid cells arise from the meiosis cell division in parent sex cells. These parent cells are divided into four cells with half of the chromosome number in comparison to the parent cells.
The gametophyte, spore, and sperm all three are the product of the meiosis division and are haploid in number.
Thus, the correct answer is option - A, gametophyte, C. spore and D. sperm.
Answer:
Nerve cells release chemical signals into synapses between them (short distance). They also transverse their lengths with an electrical signal that can result in signal travel along a series of cells (long distance).
Explanation:
Nerve cells release neurotransmitters in the synaptic cleft which are capable of affecting nearby cells such as other nerve cells and muscle cells. Neurotransmitter molecules include, among others, serotonin, acetylcholine, dopamine, norepinephrine and histamine. Moreover, the synaptic cleft is the space that separates a neuron cell and its target cell. On the other hand, neurons transmit signals through electrical impulses. Electrical impulses travel long distances in the body carried by axons of the nerves. Thus, nerve impulses connect the brain and spinal cord and they carry signals to different parts of the body.