B, both chemical and biological factors are involved
Answer:
Parental genotypes: RrBb, RRBB
Offspring phenotype: Running and black hair
Explanation:
Given, Running (R) is dominant over waltzing (r)
Black hair (B) is dominant over brown hair (b)
Parent 1: Heterozygous running, heterozygous black = RrBb
Parent 2: Homozygous running, homozygous black = RRBB
When they mate ( RrBb X RRBB ) :
Gametes produced by RrBb = RB, Rb, rB, rb
Gametes produced by RRBB = RB
Offspring:
RB Rb rB rb
RB RRBB RRBb RrBB RrBb
All offspring mice will be running mice and will have black hair because all the four types of genotype at least have one dominant allele for both the genes.
Answer:
Proper sequence of events:
5. Sensory receptor detects change in the environment.
2. Afferent neuron graded potential reaches threshold and fires an action potential.
4. CNS reaches decision about response.
1. Efferent neuron graded potential reaches threshold and fires an action potential.
3. Target organ responds.
Explanation:
Sensorial information is received by the peripheral nervous system and processed by the central nervous system. There are three types of neurons involved in this transmission: sensory or efferent neurons, interneurons, and motor or efferent neurons. First <em>stimulus energy is received</em> by sensory receptors specialized in responding to <em>different stimuli</em>. Then it occurs the <em>transduction or conversion</em> of the stimulus energy (chemical, temperature, light, pressure, etc.) to action potential energy. The afferent neurons, located in dermis and epidermis, <em>receive information</em> from the sensory receptors, react to stimuli and <em>transmit impulses</em> to the central nervous system. This pathway is defined as the <u>ascending pathway</u>. Information is <em>processed</em> in the central nervous system by the <em>interneurons</em> which handle many sensory signals, evaluate them, compare them and use them for <em>decision making.</em> After that, an efferent neuron is stimulated to <em>carry signals</em> from the central nervous system to the <em>effectors' cells</em> of the target organ. The effector may be muscle or glandular tissue. This pathway is defined as the <u>descending pathway</u>. Finally, the target organ responds by contracting or hormone-releasing.
