Consider the following points: (a) many excavates live in environments where oxygen availability is low; (b) many excavates lack mitochondria; and (c) all excavates have some mitochondrial genes. Based on this information, which of the following statements is TRUE of the excavate lineage?
a. Their ancestors were eukaryotes that existed prior to the origin of mitochondria
b. Their ancestors were not able to metabolize glucose
c. Excavates are in the process of acquiring mitochondria through evolutionary adaptation
d. Their ancestors had mitochondria, but the mitochondria were lost over time

Their ancestors had mitochondria but the mitochondria were lost over time ( D )

Explanation:

from the following points given that many excavates live in environments where oxygen is relatively low and many excavates lack Mitochondria and also that they all have Mitochondrial genes in them shows that their ancestors had mitochondria

Due to the evolution of the Excavates over time they lost their Mitochondria but the gene remained in the DNA of the excavates. the excavates are a major super group of unicellular organisms   belonging to the Domain Eukaryota.

The absence of Mitochondria which is used for biochemical respiratory purposes and energy production is the reason why many Excavates live in environments where oxygen is scarce .

after receiving a stimus, the sensory receptors send(s) signals to the appropriate area of the body.  

the must be sensory neurons.  

hope its .