I would say that the answer is D.
The answers are A) ectoderm and B) endoderm.
Fertilization is a fusion of male and female gametes which leads to the formation of a zygote. The zygote undergoes mitosis and transforms into a single-layered blastula. Gastrulation is a transformation of the blastula into a two-layer or three-layer gastrula. Cnidarians are a diploblastic animal because their gastrula has only two layers - endoderm and ectoderm.
There are two types of neurons in our legs: motor neuron and sensory neuron. These send and receive messages to and from each other and the brain.
After Ed's accident, he can't move his injured leg since the motor neuron is dysfunctional. The sensory neuron is functional so he can feel his limbs but can't move them since when the sensory neuron sends a message to the motor neuron, it isn't able to deliver the message to the brain to make the leg move. This is why he can still feel his limbs but is not able to move them.
(I wrote to you more than three types)
There are seven known types of human coronavirus. Four common types (KHUI, OC43, NL63,229E) cause mild to moderate respiratory infection, such as the common cold. There are two types, severe acute respiratory syndrome (SARS-COV) and Middle East respiratory virus syndrome (MERS-COV), that can cause acute respiratory infections. Type VII (nCOV-2019) is the newly discovered novel coronavirus in China.
