Answer: 18°24'
cos 
Explanation:
Use equation for cos α=b/c
b=32
c=40
cosα=32/40
cosα=4/5
csc=71.62°
α=71.62°
90°+α+β=180°
β=180-α-90
β=180-71,62-90
β=18.4°
β= 18°24'
 
        
             
        
        
        
Answer:
B. False
Explanation:
Life history characteristics and survivorship patterns within a species are pre-set but may be changed according to the changes in environmental conditions needed for growth and reproduction. Allocation of energy to reproduction or other processes varies according to food availability, temperature, rainfall, etc.  
Abundant resource availability favors the production of a large number of smaller offspring while limited resources make a population to produce a small number of larger progeny to increase the survival rate.  
Example: Clutch size in birds is adjusted to obtain the maximum survival of progeny.  
 
        
             
        
        
        
Answer:
Humans lack DNA in their brain cells.
Explanation:
 
        
             
        
        
        
Answer:
A neuron has a cell body, an axon and dendrites. Apart from these structures, the white myelin sheath covers the axons. The gaps where myelin sheath is absent are called nodes of Ranvier. Axon terminals are the extreme ends of the axon from where nerve impulse is carried to the dendrites of the post synaptic neuron. 
Explanation:
A neuron has a cell body, an axon, and dendrites.  
Cell body: It is the metabolic center of the neuron and does not take part in the conduction of nerve impulse.  
Axon and dendrites: These are the extensions arising from the cell body. Dendrites are smaller and more in number while axon is a single large extension.  
The function of the axon is to carry the nerve impulse from the cell body to the axon terminals. Dendrites receive the nerve impulse from the axon terminal and pass it to the cell body. The ends of axons are called axon terminals. They synapse with dendrites of postsynaptic neurons.  
The myelin sheath is the fatty layer present on long axons and serves to accelerate the rate of conduction of nerve impulse.  The nodes of Ranvier are the gaps where the myelin sheath is not present.