Soon after the discovery of nerve growth factor (ngf), researchers injected newborn mice with rabbit antiserum (i. e. rabbit serum that contains antibodies) that recognize and neutralize mouse ngf. they observed massive nerve cell death compared to appropriate control injections (e. g. injection of rabbit antiserum that doesn't recognize ngf), up to 99% of the neurons in some parts of the developing peripheral nervous system died after about a week of daily injections. which of the following conclusions is supported by these results?

a. ngf signaling sensitizes developing nerve cells to apoptotic signals.
b. developing neurons undergo apoptosis in the presence of rabbit proteins.
c. developing neurons require ngf for apoptosis.
d. developing neurons undergo cell death in the absence of ngf.
e. ngf signaling is sufficient for survival of the developing neurons.

The correct answer is D developing neurons undergo cell death in the  absence of NGF.

Explanation:

NGF or nerve growth factor is a protein that act a signaling molecule.The binding of NGF to its specific NGF receptor triggers the growth of nerve cell.

   According to the given question 99% of the mice neuron  died when newborn mice was injected with rabbit antiserum that recognizes and neutralize mouse NGF.

   In simple words it means the death of 99% of the neuron in mice occur due to absence or neutralization of NGF.

answer: grassland biomes are closer to the equator and receive more rain.

grasslands are biomes that are dominated by grasses rather shrubs and trees. savanna are biomes that exhibit grasses, shrubs and small tree as vegetation. grasslands are located near the equator of the earth. these are found in north america. savanna biomes are found in africa, south america, australia and india. grassland exhibit moderate climatic conditions, it receives   amount of rainfall higher than savanna.   therefore, savanna exhibit dry and hot climatic conditions.